CVE-2025-11738

Executive Summary

CVE-2025-11738 is a limited file read vulnerability in the Media Library Assistant plugin for WordPress, affecting all versions up to and including 3.29. The flaw resides in the mla-stream-image.php file, which fails to properly restrict file access. An unauthenticated attacker can exploit this to read arbitrary .ai, .eps, .pdf, and .ps files from the server, potentially exposing sensitive information such as design assets, configuration data, or embedded metadata.

This vulnerability is classified as a WordPress ecosystem issue and does not involve Apache or Nginx directly. The CVSS score of 5.3 (Medium) reflects the limited scope of readable file types, but the lack of authentication requirements and the potential for sensitive data exposure elevate the risk in targeted attacks.

Supply Chain & Package Security

This vulnerability is specific to the WordPress plugin ecosystem. No NPM, PyPI, Go, or Ruby packages are affected. The plugin is distributed via the WordPress Plugin Directory, and users should monitor for official updates.

CVSS Breakdown & Threat Level

• CVSS Score: 5.3 (Medium)
• Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
• Attack Vector: Network
• Attack Complexity: Low
• Privileges Required: None
• User Interaction: None
• Scope: Unchanged
• Confidentiality Impact: Low (limited to specific file types)
• Integrity Impact: None
• Availability Impact: None

The threat level is elevated due to the unauthenticated nature of the exploit and the potential for sensitive data leakage, even though only a subset of file types is accessible.

Deep Dive & Mechanics

The vulnerability exists in the mla-stream-image.php file, which is part of the Media Library Assistant plugin. This file is intended to serve image files for streaming or display. However, it fails to validate the file extension or path properly, allowing an attacker to request arbitrary files with .ai, .eps, .pdf, or .ps extensions.

The core issue is a lack of input sanitization and path traversal protection. The script likely uses a parameter (e.g., file or path) to specify the file to stream, but does not restrict the directory or file type beyond a basic check. An attacker can use path traversal sequences (e.g., ../) to navigate outside the intended directory and read sensitive files.

Example vulnerable request:

GET /wp-content/plugins/media-library-assistant/mla-stream-image.php?file=../../../../etc/passwd HTTP/1.1

However, the vulnerability is limited to .ai, .eps, .pdf, and .ps files, so the attacker would need to target files with those extensions.

Vulnerable vs. Patched Code

Since no official patch is available, the vulnerable code is presumed to be in mla-stream-image.php. A patched version would need to:

1. Validate the file extension against a whitelist of allowed types.
2. Restrict the file path to a specific directory (e.g., the uploads directory).
3. Use realpath() to resolve path traversal attempts.

Vulnerable code (conceptual):

$file = $_GET['file'];
$content = file_get_contents($file);
header('Content-Type: application/octet-stream');
echo $content;

Patched code (conceptual):

$allowed_extensions = ['jpg', 'png', 'gif', 'webp'];
$file = basename($_GET['file']);
$ext = pathinfo($file, PATHINFO_EXTENSION);
if (!in_array($ext, $allowed_extensions)) {
    die('Invalid file type');
}
$path = realpath('/var/www/html/wp-content/uploads/' . $file);
if (strpos($path, '/var/www/html/wp-content/uploads/') !== 0) {
    die('Invalid path');
}
readfile($path);

Exploitation & Lab Setup

Red Team (Offensive)

Prerequisites:

• A WordPress instance with Media Library Assistant plugin version <= 3.29.
• Knowledge of a target file with .ai, .eps, .pdf, or .ps extension.

Exploitation Steps:

1. Identify the vulnerable endpoint: http://target/wp-content/plugins/media-library-assistant/mla-stream-image.php
2. Craft a request with a path traversal payload to read a sensitive file, e.g., ../../../../wp-config.php (but note the extension limitation).
3. Since only specific extensions are readable, target files like backup.eps or design.ai in accessible directories.

Example curl command:

curl -v "http://target/wp-content/plugins/media-library-assistant/mla-stream-image.php?file=../../../../uploads/2025/01/sensitive.pdf"

Note: No public exploit code is available at this time.

Blue Team (Defensive)

Detection:

• Monitor web server logs for requests to mla-stream-image.php with suspicious file parameters containing ../ or absolute paths.
• Alert on unusual file extensions being accessed via this endpoint (e.g., .pdf, .eps).

Honeypot:

• Place a fake .pdf file named secret.pdf in the uploads directory and monitor access.

Indicators of Compromise (IOCs)

• File Path: /wp-content/plugins/media-library-assistant/mla-stream-image.php
• HTTP Request Pattern: GET /wp-content/plugins/media-library-assistant/mla-stream-image.php?file=*
• Suspicious Parameters: file containing ../, %2e%2e%2f, or absolute paths like /etc/
• Response Headers: Content-Type: application/octet-stream or application/pdf for non-image files.

Detection Engineering

YARA Rule

rule CVE_2025_11738_File_Read {
    meta:
        description = "Detects exploitation attempts of CVE-2025-11738 in Media Library Assistant plugin"
        author = "Valters IT"
        date = "2025-04-10"
        reference = "https://nvd.nist.gov/vuln/detail/CVE-2025-11738"
    strings:
        $suspicious_param = "mla-stream-image.php?file="
        $path_traversal = "../"
        $abs_path = "/etc/"
    condition:
        $suspicious_param and ($path_traversal or $abs_path)
}

Sigma Rule

title: CVE-2025-11738 - Media Library Assistant File Read Attempt
id: 7a8b9c0d-1e2f-3a4b-5c6d-7e8f9a0b1c2d
status: experimental
description: Detects attempts to exploit limited file read vulnerability in Media Library Assistant plugin
author: Valters IT
date: 2025-04-10
logsource:
    category: webserver
    product: apache
detection:
    selection:
        cs-method: 'GET'
        cs-uri-stem: '/wp-content/plugins/media-library-assistant/mla-stream-image.php'
        cs-uri-query|contains: 'file='
    condition: selection
falsepositives:
    - Legitimate use of the plugin's streaming functionality
level: medium

Suricata Rule

alert http any any -> any any (msg:"CVE-2025-11738 - Media Library Assistant File Read Attempt"; flow:to_server,established; content:"GET"; http_method; content:"/wp-content/plugins/media-library-assistant/mla-stream-image.php"; http_uri; content:"file="; http_uri; pcre:"/file=(\.\.\/|[a-zA-Z]:\\/)/Ri"; sid:1000001; rev:1;)

Remediation & Mitigation

Immediate Actions:

1. Disable the plugin if not essential, or restrict access to mla-stream-image.php via .htaccess:

   <Files "mla-stream-image.php">
       Require all denied
   </Files>
   

2. Implement a Web Application Firewall (WAF) rule to block requests with path traversal patterns in the file parameter.
3. Monitor logs for exploitation attempts.

Long-term Fix:

• Apply an official patch once released by the plugin vendor.
• Consider replacing the plugin with an alternative that has proper input validation.

Valters IT
Securing WordPress ecosystems one CVE at a time.