CVE-2026-24673
📋 TL;DR
Open eClass platform versions before 4.2 contain a file upload validation bypass vulnerability. Attackers can upload files with prohibited extensions by embedding them inside ZIP archives and exploiting the application's built-in decompression functionality. This affects all Open eClass installations running vulnerable versions.
💻 Affected Systems
- Open eClass (formerly GUnet eClass)
⚠️ Manual Verification Required
This CVE does not have specific version information in our database, so automatic vulnerability detection cannot determine if your system is affected.
Why? The CVE database entry doesn't specify which versions are vulnerable (no version ranges provided by the vendor/NVD).
🔒 Custom verification scripts are available for registered users. Sign up free to download automated test scripts.
- Review the CVE details at NVD
- Check vendor security advisories for your specific version
- Test if the vulnerability is exploitable in your environment
- Consider updating to the latest version as a precaution
⚠️ Risk & Real-World Impact
Worst Case
Attackers upload malicious files (webshells, malware) that execute on the server, potentially leading to complete system compromise, data theft, or ransomware deployment.
Likely Case
Attackers upload malicious files to gain persistent access, deface websites, or use the server for malicious activities like phishing or malware distribution.
If Mitigated
Limited impact with proper file upload restrictions, web application firewalls, and file integrity monitoring in place.
🎯 Exploit Status
Exploitation requires authenticated access to upload files. The technique is well-known and easy to implement.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 4.2
Vendor Advisory: https://github.com/gunet/openeclass/security/advisories/GHSA-3g4j-56gp-v6wv
Restart Required: Yes
Instructions:
1. Backup your Open eClass installation and database. 2. Download version 4.2 from the official repository. 3. Replace existing files with the patched version. 4. Run any database migration scripts if required. 5. Restart the web server.
🔧 Temporary Workarounds
Disable ZIP extraction functionality
allTemporarily disable the built-in decompression feature that processes uploaded ZIP files.
Modify application configuration to remove or disable ZIP processing modules
Implement server-side file extension validation
allAdd additional validation on extracted files to check for prohibited extensions regardless of archive format.
Add server-side script to scan extracted files and block prohibited extensions
🧯 If You Can't Patch
- Implement strict file upload restrictions at the web server level (e.g., .htaccess for Apache, nginx config)
- Deploy a web application firewall (WAF) with file upload protection rules
🔍 How to Verify
Check if Vulnerable:
Check if your Open eClass version is below 4.2 by examining the version file or admin panel.Check Version:
Check the version.php file or login to admin panel to view version information.Verify Fix Applied:
After upgrading to 4.2, test file upload functionality with ZIP archives containing prohibited extensions to ensure they are blocked.📡 Detection & Monitoring
Log Indicators:
- Multiple failed file upload attempts followed by successful uploads
- ZIP file uploads followed by file extraction events
- Uploads of files with double extensions or unusual names
Network Indicators:
- Unusual file upload patterns to the eClass platform
- POST requests with ZIP file content to upload endpoints
SIEM Query:
source="web_server_logs" AND (uri_path="/upload" OR uri_path="/file/upload") AND (file_extension="zip" OR content_type="application/zip")