CVE-2026-22789: WebErpMesv2 RCE Vulnerability

CVE-2026-22789 Overview

WebErpMesv2, a Resource Management and Manufacturing execution system Web for industry, contains a file upload validation bypass vulnerability in multiple controllers prior to version 1.19. This vulnerability allows authenticated users to upload arbitrary files, including PHP scripts, leading to Remote Code Execution (RCE). The vulnerability is classified as CWE-434 (Unrestricted Upload of File with Dangerous Type) and is identical in nature to CVE-2025-52130 but exists in different code locations that were not addressed by the original fix.

Critical Impact

Authenticated attackers can upload malicious PHP scripts to the server, enabling full Remote Code Execution and potential complete system compromise of manufacturing and resource management infrastructure.

Affected Products

• WebErpMesv2 versions prior to 1.19

Discovery Timeline

• 2026-01-12 - CVE CVE-2026-22789 published to NVD
• 2026-01-13 - Last updated in NVD database

Technical Details for CVE-2026-22789

Vulnerability Analysis

This vulnerability represents an unrestricted file upload flaw (CWE-434) that affects multiple controllers within the WebErpMesv2 application. The core issue stems from inadequate validation of file types during the upload process, allowing authenticated users to bypass intended security restrictions and upload executable PHP scripts to the web server.

The flaw is particularly concerning as it is a regression or incomplete fix of CVE-2025-52130. While the original vulnerability was addressed, the same validation bypass pattern exists in different code locations within the application, indicating that the initial remediation did not comprehensively address all instances of the vulnerable code pattern.

Root Cause

The root cause of this vulnerability lies in insufficient file upload validation logic across multiple controllers in the WebErpMesv2 application. The application fails to properly validate or restrict the types of files that can be uploaded by authenticated users. Specifically, the validation mechanisms do not adequately check file extensions, MIME types, or file content to prevent the upload of executable server-side scripts such as PHP files.

This incomplete validation allows attackers to bypass any client-side or superficial server-side checks by manipulating file extensions, content-type headers, or other request parameters to successfully upload malicious files.

Attack Vector

The attack is network-based and requires an authenticated user session. An attacker with valid credentials to the WebErpMesv2 system can exploit this vulnerability by:

1. Authenticating to the WebErpMesv2 application with valid credentials
2. Navigating to one of the vulnerable file upload controllers
3. Crafting a malicious PHP script (such as a web shell) and uploading it through the vulnerable endpoint
4. Accessing the uploaded PHP file via its web-accessible location to execute arbitrary commands on the server

The vulnerability targets file upload functionality that fails to enforce proper restrictions on uploaded file types. Once a PHP file is uploaded and accessible via the web server, the attacker can execute arbitrary PHP code, potentially leading to full server compromise, data exfiltration, lateral movement, or ransomware deployment.

For technical details on the vulnerability and the fix, refer to the GitHub Security Advisory GHSA-64rv-f829-x6m4.

Detection Methods for CVE-2026-22789

Indicators of Compromise

• Unexpected PHP files appearing in web-accessible upload directories
• Web server access logs showing requests to unusual PHP files in upload directories
• Suspicious file uploads with double extensions (e.g., .jpg.php, .png.php) or obfuscated filenames
• Web shell signatures or known malicious PHP patterns in uploaded content

Detection Strategies

• Implement file integrity monitoring on upload directories to detect unauthorized file additions
• Deploy web application firewall (WAF) rules to detect and block file upload attacks targeting PHP extensions
• Analyze web server logs for POST requests to upload endpoints followed by GET requests to newly created PHP files
• Use endpoint detection and response (EDR) solutions like SentinelOne to identify suspicious PHP process execution

Monitoring Recommendations

• Enable detailed logging for all file upload operations, capturing filenames, extensions, and user identities
• Monitor for unusual process spawning from web server processes (e.g., www-data or apache spawning shell commands)
• Implement real-time alerting for any executable file types uploaded to the application
• Regularly audit upload directories for files with executable extensions

How to Mitigate CVE-2026-22789

Immediate Actions Required

• Upgrade WebErpMesv2 to version 1.19 or later immediately
• Audit existing upload directories for any suspicious or unauthorized PHP files
• Review access logs for evidence of exploitation attempts
• Temporarily disable file upload functionality if immediate patching is not possible
• Restrict network access to the WebErpMesv2 application to trusted IP ranges

Patch Information

The vulnerability has been fixed in WebErpMesv2 version 1.19. The security patch is available via the GitHub Commit. Organizations running affected versions should prioritize upgrading to the patched version. Additional details about the vulnerability and fix can be found in the GitHub Security Advisory GHSA-64rv-f829-x6m4.

Workarounds

• Implement web server configuration to deny execution of PHP files in upload directories
• Configure strict file type allowlists at the web server level
• Deploy a web application firewall with rules to block malicious file uploads
• Restrict upload functionality to essential users only until patching is complete

# Apache configuration to prevent PHP execution in upload directories
<Directory "/var/www/html/weberpmes/uploads">
    php_admin_flag engine off
    <FilesMatch "\.ph(p[3-7]?|tml)$">
        Require all denied
    </FilesMatch>
</Directory>