CVE-2025-3525: GitLab CI Trigger DoS Vulnerability

CVE-2025-3525 Overview

A Denial of Service vulnerability has been identified in GitLab CE/EE that allows authenticated users with specific access permissions to disrupt service availability. The vulnerability exists in the CI triggers functionality, where specially crafted API requests can cause resource exhaustion. This issue affects a wide range of GitLab versions, spanning from version 9.0 through recent releases prior to the security patches.

Critical Impact

Authenticated attackers can exploit this vulnerability to cause service disruption by creating malicious CI triggers via the GitLab API, potentially impacting continuous integration and delivery pipelines for entire organizations.

Affected Products

• GitLab CE/EE versions 9.0 to 18.7.4
• GitLab CE/EE versions 18.8 to 18.8.4
• GitLab CE/EE versions 18.9 to 18.9.0

Discovery Timeline

• February 25, 2026 - CVE-2025-3525 published to NVD
• February 25, 2026 - GitLab releases security patch (versions 18.7.5, 18.8.5, and 18.9.1)
• February 25, 2026 - Last updated in NVD database

Technical Details for CVE-2025-3525

Vulnerability Analysis

This vulnerability is classified under CWE-770 (Allocation of Resources Without Limits or Throttling). The flaw resides in GitLab's CI trigger API endpoint, which fails to properly limit or throttle resource allocation when processing specially crafted trigger requests. An authenticated user with the appropriate permissions to create CI triggers can exploit this weakness to exhaust server resources, leading to a Denial of Service condition.

The attack requires network access and low-privileged authentication, making it exploitable by any authenticated user who has been granted CI trigger creation permissions. While the vulnerability does not impact confidentiality or integrity, it poses a significant risk to system availability.

Root Cause

The root cause stems from improper resource allocation controls in the CI trigger creation mechanism. GitLab's API does not adequately validate or limit the parameters that can be passed when creating CI triggers, allowing malicious actors to craft requests that consume excessive server resources. This falls under CWE-770, where the application allocates resources based on user input without implementing proper bounds checking or rate limiting.

Attack Vector

The attack is conducted over the network through GitLab's API interface. An authenticated attacker with permissions to create CI triggers can send specially crafted requests that exploit the resource allocation weakness. The attack does not require user interaction and can be automated to repeatedly create malicious triggers until service degradation or complete denial of service occurs.

The exploitation flow involves:

1. Authenticating to GitLab with valid credentials
2. Accessing the CI triggers API endpoint
3. Submitting malformed or resource-intensive trigger configurations
4. Repeating requests to amplify resource consumption until service availability is impacted

Detection Methods for CVE-2025-3525

Indicators of Compromise

• Unusual spikes in API requests to CI trigger endpoints from authenticated users
• Elevated memory or CPU usage on GitLab application servers correlated with trigger creation activity
• Multiple failed or malformed CI trigger creation attempts in audit logs
• Service degradation or timeout errors affecting GitLab web interface and API

Detection Strategies

• Monitor GitLab audit logs for abnormal patterns in CI trigger creation activity
• Implement rate limiting detection on API endpoints, particularly /api/v4/projects/:id/triggers
• Configure alerts for resource utilization anomalies on GitLab servers
• Review access logs for authenticated users making repetitive trigger API calls

Monitoring Recommendations

• Enable detailed logging for GitLab API requests and CI trigger operations
• Set up threshold-based alerting for CPU, memory, and connection pool exhaustion
• Monitor for unusual authentication patterns followed by API activity spikes
• Implement network traffic analysis to detect volumetric API abuse patterns

How to Mitigate CVE-2025-3525

Immediate Actions Required

• Upgrade GitLab CE/EE to patched versions 18.7.5, 18.8.5, or 18.9.1 immediately
• Review and audit CI trigger permissions across projects to ensure least-privilege access
• Monitor for signs of exploitation using the detection strategies outlined above
• Consider temporarily restricting CI trigger creation permissions to trusted users only

Patch Information

GitLab has released security patches addressing this vulnerability. Organizations should upgrade to the following fixed versions:

For detailed patch information, refer to the GitLab Release Patch Note. Additional technical details are available in the GitLab Issue Tracker Entry and the HackerOne Security Report.

Workarounds

• Restrict CI trigger creation permissions to essential personnel only until patches are applied
• Implement API rate limiting at the reverse proxy or load balancer level for trigger endpoints
• Monitor and set resource quotas for GitLab application processes to limit blast radius
• Consider network-level access controls to restrict API access to trusted IP ranges

# Example: Implementing rate limiting in nginx for GitLab API
# Add to nginx configuration for GitLab

# Define rate limiting zone for CI trigger endpoints
limit_req_zone $binary_remote_addr zone=ci_triggers:10m rate=10r/m;

# Apply to CI trigger API location
location ~ ^/api/v4/projects/[0-9]+/triggers {
    limit_req zone=ci_triggers burst=5 nodelay;
    proxy_pass http://gitlab-workhorse;
}