CVE-2023-50897: Media File Renamer File Upload Vulnerability

CVE-2023-50897 Overview

CVE-2023-50897 is an Unrestricted Upload of File with Dangerous Type vulnerability (CWE-434) affecting the Meow Apps Media File Renamer WordPress plugin. This vulnerability allows attackers to upload and execute malicious files on the target system, potentially leading to remote code execution. The flaw exists in versions up to and including 5.7.7 of the plugin.

Critical Impact

This vulnerability enables authenticated attackers with high privileges to upload malicious files that can lead to arbitrary file rename and subsequently remote code execution (RCE) on affected WordPress installations.

Affected Products

• Meow Apps Media File Renamer plugin versions through 5.7.7
• WordPress installations running vulnerable versions of the Media File Renamer plugin

Discovery Timeline

• 2026-01-05 - CVE CVE-2023-50897 published to NVD
• 2026-01-08 - Last updated in NVD database

Technical Details for CVE-2023-50897

Vulnerability Analysis

The vulnerability resides in the Media File Renamer plugin's file handling functionality. The plugin fails to properly validate file types during upload and rename operations, allowing attackers to bypass security restrictions. When exploited, this flaw permits the upload of files with dangerous types (such as PHP scripts) that can be executed on the server.

This is classified as CWE-434 (Unrestricted Upload of File with Dangerous Type), which occurs when an application allows users to upload files without properly verifying that the file content and type are safe. In WordPress environments, such vulnerabilities are particularly dangerous as they can lead to complete site compromise.

Root Cause

The root cause of this vulnerability is insufficient validation of file types in the Media File Renamer plugin's file handling routines. The plugin does not adequately verify file extensions or MIME types before processing file rename operations, allowing attackers to manipulate files in ways that can lead to code execution. The lack of proper sanitization enables malicious actors to rename legitimate files to executable formats or upload dangerous file types directly.

Attack Vector

The attack is network-based and requires high-level privileges (such as administrator access) on the WordPress installation. Despite the privilege requirement, the vulnerability's impact is severe due to scope change capability, meaning a successful exploit can affect resources beyond the vulnerable component.

An attacker with administrative access to the WordPress dashboard could:

1. Access the Media File Renamer plugin functionality
2. Exploit the arbitrary file rename capability to change file extensions
3. Rename a file containing malicious code to a PHP extension
4. Execute the renamed file to achieve remote code execution on the server

The vulnerability mechanism involves improper input validation during file operations. Attackers can leverage the plugin's rename functionality to manipulate file extensions, effectively bypassing WordPress security controls. For detailed technical information, see the Patchstack WordPress Vulnerability Report.

Detection Methods for CVE-2023-50897

Indicators of Compromise

• Unexpected PHP files appearing in the wp-content/uploads/ directory
• Suspicious file rename activity in WordPress media library logs
• New or modified files with executable extensions in media directories
• Unauthorized access attempts to the Media File Renamer plugin settings

Detection Strategies

• Monitor WordPress plugin activity logs for unusual file rename operations
• Implement file integrity monitoring on the wp-content/uploads/ directory
• Review web server access logs for requests to unexpected PHP files in media directories
• Deploy Web Application Firewall (WAF) rules to detect malicious file upload attempts

Monitoring Recommendations

• Enable detailed logging for the Media File Renamer plugin operations
• Configure alerts for new executable files created in upload directories
• Implement real-time file system monitoring for WordPress installations
• Regularly audit user accounts with administrative privileges

How to Mitigate CVE-2023-50897

Immediate Actions Required

• Update the Media File Renamer plugin to a version newer than 5.7.7 immediately
• Review and audit all files in the wp-content/uploads/ directory for suspicious content
• Restrict administrative access to only trusted users
• Implement principle of least privilege for WordPress user accounts

Patch Information

Organizations using the Meow Apps Media File Renamer plugin should update to the latest available version that addresses this vulnerability. The affected versions include all releases from n/a through 5.7.7. Consult the Patchstack WordPress Vulnerability Report for additional patch details and remediation guidance.

Workarounds

• Disable the Media File Renamer plugin until it can be updated
• Implement server-level restrictions on executable file types in upload directories
• Configure .htaccess rules to prevent PHP execution in the uploads directory
• Use security plugins to monitor and block suspicious file operations

# Apache .htaccess configuration to prevent PHP execution in uploads
# Add this to wp-content/uploads/.htaccess
<FilesMatch "\.(?:php|phtml|php3|php4|php5|php7|phps)$">
    Order Allow,Deny
    Deny from all
</FilesMatch>

# For Nginx, add to server configuration:
# location ~* /wp-content/uploads/.*\.php$ {
#     deny all;
# }