CVE-2025-6454
📋 TL;DR
This vulnerability allows authenticated users in GitLab to inject crafted sequences that bypass proxy environment restrictions, enabling unintended internal requests. It affects all GitLab CE/EE instances running vulnerable versions, potentially exposing internal network resources to authenticated attackers.
💻 Affected Systems
- GitLab Community Edition
- GitLab Enterprise Edition
📦 What is this software?
Gitlab by Gitlab
GitLab is a complete DevOps platform providing source code management, CI/CD pipelines, security scanning, container registry, and collaboration tools used by millions of developers and thousands of enterprises worldwide. As both a cloud-hosted SaaS offering (GitLab.com) and self-managed software, G...
Learn more about Gitlab →Gitlab by Gitlab
GitLab is a complete DevOps platform providing source code management, CI/CD pipelines, security scanning, container registry, and collaboration tools used by millions of developers and thousands of enterprises worldwide. As both a cloud-hosted SaaS offering (GitLab.com) and self-managed software, G...
Learn more about Gitlab →Gitlab by Gitlab
GitLab is a complete DevOps platform providing source code management, CI/CD pipelines, security scanning, container registry, and collaboration tools used by millions of developers and thousands of enterprises worldwide. As both a cloud-hosted SaaS offering (GitLab.com) and self-managed software, G...
Learn more about Gitlab →Gitlab by Gitlab
GitLab is a complete DevOps platform providing source code management, CI/CD pipelines, security scanning, container registry, and collaboration tools used by millions of developers and thousands of enterprises worldwide. As both a cloud-hosted SaaS offering (GitLab.com) and self-managed software, G...
Learn more about Gitlab →Gitlab by Gitlab
GitLab is a complete DevOps platform providing source code management, CI/CD pipelines, security scanning, container registry, and collaboration tools used by millions of developers and thousands of enterprises worldwide. As both a cloud-hosted SaaS offering (GitLab.com) and self-managed software, G...
Learn more about Gitlab →Gitlab by Gitlab
GitLab is a complete DevOps platform providing source code management, CI/CD pipelines, security scanning, container registry, and collaboration tools used by millions of developers and thousands of enterprises worldwide. As both a cloud-hosted SaaS offering (GitLab.com) and self-managed software, G...
Learn more about Gitlab →⚠️ Risk & Real-World Impact
Worst Case
Authenticated attackers could pivot through proxy environments to access internal services, potentially leading to data exfiltration, lateral movement, or service disruption of internal systems.
Likely Case
Attackers with valid credentials could bypass proxy restrictions to make unauthorized requests to internal APIs or services, potentially accessing sensitive data or performing unauthorized actions.
If Mitigated
With proper network segmentation and proxy configuration validation, the impact is limited to the GitLab instance itself rather than broader internal network exposure.
🎯 Exploit Status
Exploitation requires authenticated access and knowledge of proxy environment; no public exploit code available at disclosure.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 18.1.6, 18.2.6, or 18.3.2
Vendor Advisory: https://about.gitlab.com/releases/2025/09/10/patch-release-gitlab-18-3-2-released/
Restart Required: Yes
Instructions:
1. Backup GitLab instance. 2. Update to patched version via package manager (apt/yum) or Omnibus. 3. Run 'gitlab-ctl reconfigure'. 4. Restart GitLab services.
🔧 Temporary Workarounds
Proxy Request Validation
allImplement additional validation layers in proxy configurations to reject crafted sequences
# Configure proxy to validate request patterns
# Add regex filtering for suspicious sequences
Network Segmentation
allRestrict GitLab proxy access to only necessary internal services
# Configure firewall rules to limit proxy destinations
# Implement network ACLs for GitLab proxy traffic
🧯 If You Can't Patch
- Implement strict network segmentation to isolate GitLab proxy from sensitive internal services
- Enhance monitoring for unusual proxy request patterns and implement rate limiting
🔍 How to Verify
Check if Vulnerable:
Check GitLab version via admin interface or command line; compare against affected version rangesCheck Version:
sudo gitlab-rake gitlab:env:info | grep 'Version:'Verify Fix Applied:
Confirm version is 18.1.6+, 18.2.6+, or 18.3.2+ and test proxy request functionality📡 Detection & Monitoring
Log Indicators:
- Unusual proxy request patterns
- Requests with crafted sequences in URLs
- Failed proxy authentication attempts from authenticated users
Network Indicators:
- Unexpected internal service requests originating from GitLab proxy
- Unusual traffic patterns from GitLab to internal services
SIEM Query:
source="gitlab" AND (message="*proxy*" OR message="*crafted*" OR message="*sequence*") AND severity>=WARNING