CVE-2025-13928: GitLab CE/EE DoS Vulnerability

CVE-2025-13928 Overview

CVE-2025-13928 is an incorrect authorization vulnerability affecting GitLab CE/EE that could allow an unauthenticated user to cause a denial of service condition. The vulnerability exists in API endpoints that fail to properly validate authorization, enabling attackers to exploit this weakness without any authentication credentials.

Critical Impact

Unauthenticated attackers can exploit incorrect authorization validation in GitLab API endpoints to trigger a denial of service condition, potentially disrupting critical DevOps workflows and CI/CD pipelines for organizations relying on GitLab infrastructure.

Affected Products

• GitLab CE/EE versions 17.7 through 18.6.3
• GitLab CE/EE versions 18.7.0 through 18.7.1
• GitLab CE/EE versions 18.8.0 through 18.8.1

Discovery Timeline

• 2026-01-21 - GitLab releases security patch in version 18.8.2
• 2026-01-22 - CVE-2025-13928 published to NVD
• 2026-01-22 - Last updated in NVD database

Technical Details for CVE-2025-13928

Vulnerability Analysis

This vulnerability is classified under CWE-863 (Incorrect Authorization), indicating that the affected GitLab API endpoints do not properly verify that a user is authorized to perform a requested action. The flaw enables network-based attacks that require no authentication or user interaction, making it particularly dangerous for publicly accessible GitLab instances.

The vulnerability's impact is confined to availability—attackers cannot leverage this flaw to access confidential data or modify system integrity. However, the ability to trigger a denial of service condition remotely and without credentials presents a significant operational risk, especially for organizations where GitLab serves as a critical component of their software development lifecycle.

Root Cause

The root cause lies in incorrect authorization validation logic within specific GitLab API endpoints. The affected code paths fail to properly verify whether incoming requests originate from authenticated and authorized users before processing potentially resource-intensive operations. This oversight allows unauthenticated requests to consume server resources, ultimately leading to service degradation or complete unavailability.

Attack Vector

The attack can be executed remotely over the network without requiring any authentication credentials. An attacker can send specially crafted requests to vulnerable API endpoints, bypassing authorization checks that should restrict access to authenticated users only. The low complexity of exploitation combined with no required privileges makes this vulnerability accessible to a wide range of threat actors.

The attack flow involves identifying vulnerable API endpoints, crafting requests that exploit the authorization bypass, and repeatedly sending these requests to exhaust server resources or trigger error conditions that degrade service availability.

Detection Methods for CVE-2025-13928

Indicators of Compromise

• Unusual spikes in API request volume from unauthenticated sources targeting GitLab endpoints
• Increased server resource consumption (CPU, memory) without corresponding legitimate user activity
• Error logs showing repeated authorization failures or unusual API access patterns
• Service degradation or unavailability reports coinciding with abnormal traffic patterns

Detection Strategies

• Monitor GitLab API access logs for unauthenticated requests to sensitive endpoints at abnormal volumes
• Implement rate limiting and anomaly detection for API traffic patterns
• Configure alerts for sudden increases in 4xx/5xx HTTP response codes from GitLab services
• Deploy web application firewall (WAF) rules to detect and block suspicious request patterns

Monitoring Recommendations

• Enable detailed logging for GitLab API endpoints to capture request metadata and source information
• Establish baseline metrics for normal API traffic volume and resource consumption
• Configure real-time alerting for deviations from established baselines
• Integrate GitLab logs with SIEM solutions for centralized monitoring and correlation

How to Mitigate CVE-2025-13928

Immediate Actions Required

• Upgrade GitLab CE/EE to version 18.8.2, 18.7.2, or 18.6.4 depending on your current version branch
• Review API access logs for signs of exploitation attempts prior to patching
• Implement network-level rate limiting for GitLab API endpoints as a temporary protective measure
• Consider restricting public access to GitLab instances until patches are applied

Patch Information

GitLab has released patched versions addressing this vulnerability. Organizations should upgrade to GitLab CE/EE version 18.8.2, 18.7.2, or 18.6.4 based on their deployment track. Detailed patch information is available in the GitLab Patch Release Notes. Additional technical details can be found in the GitLab Issue Tracker and the HackerOne Security Report.

Workarounds

• Implement network-level access controls to restrict API access to trusted IP ranges until patching is complete
• Deploy a reverse proxy or WAF with rate limiting capabilities in front of GitLab instances
• Monitor and temporarily block IP addresses exhibiting suspicious API access patterns
• Consider temporarily disabling non-essential API functionality if immediate patching is not feasible

# Example: Rate limiting with nginx as reverse proxy
# Add to nginx configuration for GitLab
limit_req_zone $binary_remote_addr zone=gitlab_api:10m rate=10r/s;

location /api/ {
    limit_req zone=gitlab_api burst=20 nodelay;
    proxy_pass http://gitlab_backend;
}