CVE-2025-23369
📋 TL;DR
This vulnerability allows unauthorized internal users to spoof cryptographic signatures in GitHub Enterprise Server, potentially bypassing authentication mechanisms. It affects organizations using SAML single sign-on where attackers are existing users. Only instances with specific configurations are vulnerable.
💻 Affected Systems
- GitHub Enterprise Server
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Unauthorized internal users could impersonate legitimate users, gain elevated privileges, access sensitive repositories, and potentially compromise the entire GitHub Enterprise Server instance.
Likely Case
Internal attackers with existing user accounts could bypass SAML authentication to access resources they shouldn't have permission to view or modify.
If Mitigated
With proper access controls and monitoring, impact would be limited to attempted unauthorized access that could be detected and blocked.
🎯 Exploit Status
Requires attacker to be an existing internal user with knowledge of the vulnerability and ability to manipulate cryptographic signatures.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 3.12.14, 3.13.10, 3.14.7, 3.15.2, or 3.16.0
Vendor Advisory: https://docs.github.com/en/enterprise-server@3.12/admin/release-notes#3.12.14
Restart Required: No
Instructions:
1. Backup your GitHub Enterprise Server instance. 2. Upgrade to version 3.12.14, 3.13.10, 3.14.7, 3.15.2, or 3.16.0 depending on your current version. 3. Verify the upgrade completed successfully.
🔧 Temporary Workarounds
Disable SAML SSO
allTemporarily disable SAML single sign-on if not required, which removes the vulnerable component
Restrict internal user access
allImplement strict access controls and monitor internal user activities more closely
🧯 If You Can't Patch
- Implement network segmentation to isolate GitHub Enterprise Server from untrusted internal networks
- Enable enhanced logging and monitoring for authentication events and user privilege changes
🔍 How to Verify
Check if Vulnerable:
Check your GitHub Enterprise Server version via the Management Console or SSH into the appliance and run 'ghe-version'Check Version:
ghe-versionVerify Fix Applied:
After patching, verify the version shows 3.12.14, 3.13.10, 3.14.7, 3.15.2, or 3.16.0 or higher📡 Detection & Monitoring
Log Indicators:
- Unusual authentication patterns, multiple failed SAML authentication attempts followed by success, user privilege escalation without proper workflow
Network Indicators:
- Unusual internal network traffic to GitHub Enterprise Server authentication endpoints
SIEM Query:
source="github-enterprise" AND (event_type="authentication" AND result="success" AND user_agent="unusual") OR (event_type="permission_change" AND actor!=admin)🔗 References
- https://docs.github.com/en/enterprise-server@3.12/admin/release-notes#3.12.14
- https://docs.github.com/en/enterprise-server@3.13/admin/release-notes#3.13.10
- https://docs.github.com/en/enterprise-server@3.14/admin/release-notes#3.14.7
- https://docs.github.com/en/enterprise-server@3.15/admin/release-notes#3.15.2
