CVE-2025-68925
📋 TL;DR
Jervis versions before 2.2 fail to validate JWT algorithm headers, allowing attackers to forge tokens using weaker algorithms like 'none' or HMAC. This affects Jenkins pipeline users who rely on Jervis for Job DSL plugin scripts and shared libraries. Attackers could bypass authentication or authorization controls.
💻 Affected Systems
- Jervis
📦 What is this software?
Jervis by Samrocketman
⚠️ Risk & Real-World Impact
Worst Case
Complete Jenkins pipeline compromise allowing unauthorized job execution, credential theft, and lateral movement within CI/CD infrastructure.
Likely Case
Unauthorized access to Jenkins jobs and pipelines, potentially modifying build processes or accessing sensitive build artifacts.
If Mitigated
Limited impact with proper network segmentation and minimal Jenkins privileges, though authentication bypass remains possible.
🎯 Exploit Status
Exploitation requires ability to generate JWTs and knowledge of Jervis usage in target Jenkins instance.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 2.2
Vendor Advisory: https://github.com/samrocketman/jervis/security/advisories/GHSA-5pq9-5mpr-jj85
Restart Required: Yes
Instructions:
1. Update Jervis library to version 2.2 or later
2. Restart Jenkins service
3. Verify JWT validation is now enforced
🔧 Temporary Workarounds
Disable Jervis usage
allTemporarily stop using Jervis library in Jenkins pipelines
Remove or comment out Jervis imports from Jenkinsfiles
🧯 If You Can't Patch
- Implement strict network controls to limit Jenkins API access
- Monitor for unusual JWT usage patterns in Jenkins logs
🔍 How to Verify
Check if Vulnerable:
Check Jervis version in Jenkins plugin manager or pipeline libraries configurationCheck Version:
Check Jenkins plugin manager or review pipeline library configuration filesVerify Fix Applied:
Attempt to use JWT with 'alg':'none' header - should be rejected in version 2.2+📡 Detection & Monitoring
Log Indicators:
- Failed JWT validation attempts
- Unusual pipeline execution patterns
- Authentication events with unexpected JWT algorithms
Network Indicators:
- Unusual API calls to Jenkins from unexpected sources
- JWT tokens with 'alg':'none' in headers
SIEM Query:
source="jenkins.log" AND ("JWT validation failed" OR "invalid algorithm" OR "alg: none")