CVE-2025-1477: GitLab CE/EE DOS Vulnerability

CVE-2025-1477 Overview

A denial of service vulnerability has been discovered in GitLab CE/EE affecting all versions from 8.14 before 18.0.6, 18.1 before 18.1.4, and 18.2 before 18.2.2. This vulnerability allows an unauthenticated user to create a denial of service condition by sending specially crafted payloads to specific integration API endpoints. The flaw is classified under CWE-770 (Allocation of Resources Without Limits or Throttling), indicating improper resource management that can be exploited to exhaust system resources.

Critical Impact

Unauthenticated attackers can disrupt GitLab services by sending malicious payloads to integration API endpoints, potentially causing service outages for development teams and CI/CD pipelines.

Affected Products

• GitLab Community Edition (CE) versions 8.14 to before 18.0.6
• GitLab Enterprise Edition (EE) versions 8.14 to before 18.0.6
• GitLab CE/EE versions 18.1 to before 18.1.4
• GitLab CE/EE versions 18.2 to before 18.2.2

Discovery Timeline

• 2025-08-13 - CVE-2025-1477 published to NVD
• 2025-08-15 - Last updated in NVD database

Technical Details for CVE-2025-1477

Vulnerability Analysis

This vulnerability exists within GitLab's integration API endpoints, which are designed to facilitate communication between GitLab and external services such as Jira, Slack, and other third-party integrations. The core issue stems from insufficient resource allocation controls when processing incoming requests to these endpoints.

The vulnerability allows unauthenticated users to submit specially crafted payloads that trigger excessive resource consumption on the GitLab server. This resource exhaustion attack does not require any form of authentication, significantly lowering the barrier for exploitation. The impact is limited to availability—there is no compromise of data confidentiality or integrity.

Root Cause

The root cause of CVE-2025-1477 is CWE-770: Allocation of Resources Without Limits or Throttling. GitLab's integration API endpoints lack proper rate limiting and resource allocation boundaries when processing incoming payloads. Without these protective measures, an attacker can craft requests that consume disproportionate amounts of server resources (CPU, memory, or network connections), leading to service degradation or complete unavailability.

Attack Vector

The attack is network-based and can be executed remotely without authentication. An attacker targets the integration API endpoints, which are typically exposed to facilitate webhook integrations and third-party service communications.

The attack workflow involves:

1. Identifying exposed GitLab integration API endpoints
2. Crafting malicious payloads designed to consume excessive resources
3. Sending repeated or oversized requests to trigger resource exhaustion
4. The GitLab server becomes overwhelmed, causing denial of service for legitimate users

Since no authentication is required, any attacker with network access to the GitLab instance can exploit this vulnerability. Self-hosted GitLab instances exposed to the internet are particularly at risk.

Detection Methods for CVE-2025-1477

Indicators of Compromise

• Unusual spike in requests to integration API endpoints from single or multiple IP addresses
• Elevated resource consumption (CPU, memory) correlating with API endpoint activity
• GitLab service degradation or unresponsiveness during periods of high integration API traffic
• Log entries showing repeated requests to integration-related endpoints without valid authentication

Detection Strategies

• Monitor GitLab application logs for anomalous request patterns to /api/*/integrations and related endpoints
• Implement rate limiting alerts at the network or application layer for integration API endpoints
• Configure monitoring for unusual resource utilization patterns on GitLab servers
• Deploy Web Application Firewall (WAF) rules to detect oversized or malformed payloads targeting integration endpoints

Monitoring Recommendations

• Enable detailed logging for GitLab integration API endpoints to capture request metadata
• Set up alerting thresholds for API request rates that exceed normal operational baselines
• Monitor server resource metrics (CPU, memory, network I/O) with correlation to API activity
• Review GitLab audit logs periodically for patterns consistent with denial of service attempts

How to Mitigate CVE-2025-1477

Immediate Actions Required

• Upgrade GitLab CE/EE to version 18.0.6, 18.1.4, or 18.2.2 or later immediately
• Implement network-level rate limiting for integration API endpoints pending upgrade
• Review firewall rules to restrict integration API access to known trusted sources where possible
• Consider temporarily disabling unused integrations until patching is complete

Patch Information

GitLab has addressed this vulnerability in the following versions:

• 18.0.6 for the 18.0.x branch
• 18.1.4 for the 18.1.x branch
• 18.2.2 for the 18.2.x branch

For additional details, refer to the GitLab Issue Report and the HackerOne Vulnerability Report.

Organizations running affected versions should prioritize patching, particularly for internet-facing GitLab instances.

Workarounds

• Implement rate limiting at the reverse proxy or load balancer level for integration API endpoints
• Restrict access to integration API endpoints to known IP ranges using firewall rules
• Deploy a Web Application Firewall (WAF) with rules to block oversized or anomalous payloads
• Monitor and alert on integration API endpoint abuse patterns while awaiting patch deployment

# Example: nginx rate limiting configuration for GitLab integration endpoints
# Add to nginx configuration for GitLab

limit_req_zone $binary_remote_addr zone=integration_limit:10m rate=10r/s;

location ~ ^/api/.*/integrations {
    limit_req zone=integration_limit burst=20 nodelay;
    proxy_pass http://gitlab-workhorse;
}