CVE-2026-1102
📋 TL;DR
This vulnerability in GitLab allows unauthenticated attackers to cause denial of service by sending repeated malformed SSH authentication requests. It affects all GitLab CE/EE installations running vulnerable versions, potentially making services unavailable to legitimate users.
💻 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
Complete service unavailability for all GitLab users, disrupting development workflows and CI/CD pipelines.
Likely Case
Intermittent service degradation or temporary unavailability affecting SSH-based operations.
If Mitigated
Minimal impact with proper network controls and rate limiting in place.
🎯 Exploit Status
Attack requires no authentication and uses simple malformed SSH requests. Easy to automate for DoS attacks.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 18.6.4, 18.7.2, or 18.8.2
Vendor Advisory: https://about.gitlab.com/releases/2026/01/21/patch-release-gitlab-18-8-2-released/
Restart Required: Yes
Instructions:
1. Backup your GitLab instance. 2. Update to patched version using your package manager. 3. Restart GitLab services. 4. Verify the update was successful.
🔧 Temporary Workarounds
SSH Rate Limiting
linuxImplement rate limiting for SSH connections to prevent repeated malicious requests
# Configure iptables to limit SSH connections
iptables -A INPUT -p tcp --dport 22 -m state --state NEW -m recent --set
iptables -A INPUT -p tcp --dport 22 -m state --state NEW -m recent --update --seconds 60 --hitcount 10 -j DROP
Network Segmentation
linuxRestrict SSH access to trusted networks only
# Allow SSH only from specific IP ranges
iptables -A INPUT -p tcp --dport 22 -s 192.168.1.0/24 -j ACCEPT
iptables -A INPUT -p tcp --dport 22 -j DROP
🧯 If You Can't Patch
- Implement strict network ACLs to limit SSH access to trusted sources only
- Deploy WAF or load balancer with rate limiting for SSH traffic
🔍 How to Verify
Check if Vulnerable:
Check GitLab version and compare against affected ranges: 12.3-18.6.3, 18.7-18.7.1, 18.8-18.8.1Check Version:
sudo gitlab-rake gitlab:env:info | grep 'GitLab Version'Verify Fix Applied:
Confirm GitLab version is 18.6.4, 18.7.2, or 18.8.2 or higher📡 Detection & Monitoring
Log Indicators:
- High volume of failed SSH authentication attempts
- SSH connection timeouts or errors in GitLab logs
- Unusual patterns of malformed SSH requests
Network Indicators:
- Spike in SSH traffic from single or multiple sources
- Repeated SSH connection attempts with malformed packets
SIEM Query:
source="gitlab.logs" AND ("ssh authentication failed" OR "malformed ssh") | stats count by src_ip