CVE-2026-22218
📋 TL;DR
Chainlit versions before 2.9.4 contain an arbitrary file read vulnerability where authenticated clients can manipulate element paths to copy server files into their session, then retrieve those files via API. This allows attackers to read any file accessible to the Chainlit service, potentially exposing sensitive data. All deployments using vulnerable versions are affected.
💻 Affected Systems
- Chainlit
📦 What is this software?
Chainlit by Chainlit
⚠️ Risk & Real-World Impact
Worst Case
Complete compromise of sensitive server files including configuration files, credentials, source code, and user data, potentially leading to full system takeover.
Likely Case
Exfiltration of configuration files, API keys, database credentials, and other sensitive data stored on the server.
If Mitigated
Limited impact if proper authentication controls and file system permissions restrict access to sensitive files.
🎯 Exploit Status
Exploitation requires authenticated access but is straightforward once authenticated.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 2.9.4
Vendor Advisory: https://github.com/Chainlit/chainlit/releases/tag/2.9.4
Restart Required: Yes
Instructions:
1. Update Chainlit to version 2.9.4 or later using pip: pip install chainlit>=2.9.4
2. Restart all Chainlit services
3. Verify the update was successful
🔧 Temporary Workarounds
Restrict File System Access
allRun Chainlit service with minimal file system permissions using containerization or restricted user accounts
docker run --read-only -v /tmp:/tmp chainlit_app
sudo -u chainlit_user python -m chainlit run app.py
Network Segmentation
linuxRestrict access to Chainlit service to trusted networks only
iptables -A INPUT -p tcp --dport 8000 -s trusted_network -j ACCEPT
iptables -A INPUT -p tcp --dport 8000 -j DROP
🧯 If You Can't Patch
- Implement strict authentication and authorization controls to limit who can access the Chainlit service
- Deploy network monitoring and file access auditing to detect exploitation attempts
🔍 How to Verify
Check if Vulnerable:
Check Chainlit version: python -c "import chainlit; print(chainlit.__version__)" and verify if it's below 2.9.4Check Version:
python -c "import chainlit; print(chainlit.__version__)"Verify Fix Applied:
Confirm version is 2.9.4 or higher: python -c "import chainlit; print(chainlit.__version__)"📡 Detection & Monitoring
Log Indicators:
- Unusual file access patterns in /project/element endpoints
- Multiple requests to /project/file/ with sequential or unusual chainlitKey values
- Access to sensitive file paths in element update requests
Network Indicators:
- Unusual spikes in requests to /project/file/ endpoints
- Patterns of file retrieval from non-standard paths
SIEM Query:
source="chainlit.logs" AND (uri_path="/project/element" OR uri_path="/project/file/") AND (file_path CONTAINS "/etc/" OR file_path CONTAINS "/root/" OR file_path CONTAINS "/home/")