CVE-2025-25155: Music Sheet Viewer Path Traversal Flaw

CVE-2025-25155 Overview

CVE-2025-25155 is a Path Traversal vulnerability affecting the Music Sheet Viewer WordPress plugin developed by efreja. This improper limitation of a pathname to a restricted directory (CWE-22) allows unauthenticated attackers to read arbitrary files from the server by manipulating file path parameters. The vulnerability enables unauthorized access to sensitive system files outside the intended web directory.

Critical Impact

Unauthenticated remote attackers can exploit this vulnerability to read sensitive files from the server, potentially exposing configuration files, credentials, and other confidential data stored on WordPress installations.

Affected Products

• Music Sheet Viewer WordPress Plugin version 4.1 and earlier
• All WordPress installations using vulnerable versions of music-sheet-viewer
• Web servers hosting affected WordPress sites

Discovery Timeline

• 2025-02-07 - CVE-2025-25155 published to NVD
• 2026-04-23 - Last updated in NVD database

Technical Details for CVE-2025-25155

Vulnerability Analysis

This Path Traversal vulnerability exists in the Music Sheet Viewer WordPress plugin due to insufficient validation of user-supplied file path inputs. The plugin fails to properly sanitize directory traversal sequences (such as ../) in file path parameters, allowing attackers to escape the intended directory and access files anywhere on the filesystem that the web server process has permission to read.

The attack can be executed remotely over the network without requiring any authentication or user interaction. Successful exploitation leads to unauthorized disclosure of sensitive information, though it does not directly enable modification of files or denial of service.

Root Cause

The root cause stems from improper input validation within the Music Sheet Viewer plugin's file handling functionality. The plugin accepts user-controlled file path parameters without adequately filtering or sanitizing path traversal sequences. This allows malicious actors to craft requests containing directory traversal patterns that navigate outside the plugin's designated file storage directory.

WordPress plugins that handle file operations must implement strict path canonicalization and validation to ensure requested files reside within permitted directories. The absence of such controls in versions 4.1 and earlier of this plugin creates an arbitrary file read condition.

Attack Vector

The vulnerability is exploitable via network-based requests to the WordPress site hosting the vulnerable plugin. An attacker can craft malicious HTTP requests that include path traversal sequences in file parameters. By traversing up the directory structure with sequences like ../../../, the attacker can specify paths to sensitive files such as /etc/passwd, wp-config.php, or other configuration files containing database credentials and authentication keys.

No authentication is required to exploit this vulnerability, making it particularly dangerous for publicly accessible WordPress installations. The attacker only needs network access to the target web server to attempt exploitation.

For technical details on the exploitation mechanism, refer to the Patchstack Vulnerability Report.

Detection Methods for CVE-2025-25155

Indicators of Compromise

• HTTP requests to WordPress endpoints containing path traversal sequences such as ../, ..%2f, or ..%252f
• Unusual access patterns to the music-sheet-viewer plugin endpoints
• Web server logs showing requests attempting to access sensitive files like wp-config.php, /etc/passwd, or .htaccess
• Spike in 404 or 200 responses from plugin file handling endpoints with suspicious path parameters

Detection Strategies

• Implement web application firewall (WAF) rules to detect and block path traversal patterns in URL parameters and request bodies
• Configure intrusion detection systems to alert on requests containing encoded directory traversal sequences
• Review WordPress access logs for anomalous requests targeting the music-sheet-viewer plugin
• Deploy file integrity monitoring to detect unauthorized access attempts to sensitive configuration files

Monitoring Recommendations

• Enable detailed logging for the WordPress installation and web server
• Monitor for repeated requests from single IP addresses targeting plugin endpoints
• Set up alerting for access attempts to sensitive files outside the web root
• Regularly audit installed plugins for known vulnerabilities using WordPress security scanning tools

How to Mitigate CVE-2025-25155

Immediate Actions Required

• Update the Music Sheet Viewer plugin to the latest patched version immediately
• If no patch is available, disable and remove the music-sheet-viewer plugin until a fix is released
• Implement WAF rules to block path traversal patterns as a temporary mitigation
• Review server logs for evidence of exploitation attempts
• Rotate any credentials that may have been exposed, particularly WordPress database credentials and authentication keys

Patch Information

Users should check for updates to the Music Sheet Viewer plugin through the WordPress admin dashboard or by visiting the plugin's page on WordPress.org. The Patchstack Vulnerability Report provides additional details on affected versions and remediation guidance.

Workarounds

• Disable the Music Sheet Viewer plugin entirely if updates are not available
• Implement strict input validation at the web server level using .htaccess rules or server configuration to block traversal patterns
• Use a web application firewall to filter malicious requests before they reach WordPress
• Restrict file system permissions to limit the web server's access to only necessary directories
• Consider placing sensitive configuration files outside the web root where possible

# Example .htaccess rules to block common path traversal patterns
<IfModule mod_rewrite.c>
    RewriteEngine On
    RewriteCond %{QUERY_STRING} (\.\./|\.\.%2f|\.\.%252f) [NC,OR]
    RewriteCond %{REQUEST_URI} (\.\./|\.\.%2f|\.\.%252f) [NC]
    RewriteRule .* - [F,L]
</IfModule>