CVE-2025-6776
📋 TL;DR
This critical vulnerability in xiaoyunjie openvpn-cms-flask allows remote attackers to perform path traversal attacks via the image upload function. Attackers can write arbitrary files to unintended locations on the server, potentially leading to remote code execution. All systems running openvpn-cms-flask versions up to 1.2.7 are affected.
💻 Affected Systems
- xiaoyunjie openvpn-cms-flask
📦 What is this software?
Openvpn Cms Flask by Xiaoyunjie
⚠️ Risk & Real-World Impact
Worst Case
Remote code execution leading to complete system compromise, data exfiltration, and lateral movement within the network.
Likely Case
Arbitrary file upload leading to web shell deployment, data manipulation, or denial of service.
If Mitigated
Limited impact with proper file upload restrictions and web application firewalls in place.
🎯 Exploit Status
Exploit has been publicly disclosed and requires file upload access
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 1.2.8
Vendor Advisory: https://github.com/xiaoyunjie/openvpn-cms-flask/releases/tag/v1.2.8
Restart Required: Yes
Instructions:
1. Backup current configuration and data. 2. Stop the openvpn-cms-flask service. 3. Upgrade to version 1.2.8 using pip: 'pip install openvpn-cms-flask==1.2.8'. 4. Restart the service.
🔧 Temporary Workarounds
Disable file upload functionality
allTemporarily disable the vulnerable file upload endpoint
Modify app/plugins/oss/app/controller.py to comment out or remove the Upload function
Implement WAF rules
allAdd web application firewall rules to block path traversal attempts
Add WAF rule to block requests containing '../' or similar path traversal patterns in file upload parameters
🧯 If You Can't Patch
- Implement strict file upload validation including file type checking and path sanitization
- Deploy network segmentation to isolate the vulnerable system from critical assets
🔍 How to Verify
Check if Vulnerable:
Check the version of openvpn-cms-flask installed: 'pip show openvpn-cms-flask' and verify if version is <=1.2.7Check Version:
pip show openvpn-cms-flask | grep VersionVerify Fix Applied:
Verify installation of version 1.2.8: 'pip show openvpn-cms-flask | grep Version' should show 1.2.8📡 Detection & Monitoring
Log Indicators:
- Unusual file upload attempts with path traversal patterns (../, ..\)
- File writes to unexpected directories
- Multiple failed upload attempts
Network Indicators:
- HTTP POST requests to /upload endpoints containing path traversal sequences
- Unusual outbound connections from the server after file uploads
SIEM Query:
source="web_logs" AND (uri_path="/upload" OR uri_path="/api/upload") AND (request_body CONTAINS "../" OR request_body CONTAINS "..\")🔗 References
- https://github.com/xiaoyunjie/openvpn-cms-flask/commit/e23559b98c8ea2957f09978c29f4e512ba789eb6
- https://github.com/xiaoyunjie/openvpn-cms-flask/issues/23
- https://github.com/xiaoyunjie/openvpn-cms-flask/releases/tag/v1.2.8
- https://vuldb.com/?ctiid.314092
- https://vuldb.com/?id.314092
- https://vuldb.com/?submit.602374
