CVE-2025-10497: GitLab Denial of Service Vulnerability

CVE-2025-10497 Overview

A denial of service vulnerability has been identified in GitLab CE/EE that allows an unauthenticated attacker to cause service disruption by sending specially crafted payloads. This vulnerability affects GitLab installations across multiple versions and can be exploited remotely without requiring any authentication, making it a significant threat to organizations relying on GitLab for their development workflows.

The vulnerability is classified under CWE-770 (Allocation of Resources Without Limits or Throttling), indicating that the application fails to properly limit or throttle resource allocation when processing certain inputs. This allows attackers to exhaust system resources and render the GitLab instance unavailable to legitimate users.

Critical Impact

Unauthenticated attackers can remotely trigger denial of service conditions, potentially disrupting software development pipelines, CI/CD processes, and collaborative workflows for organizations using affected GitLab versions.

Affected Products

• GitLab Community Edition (CE) versions 17.10 through 18.3.4
• GitLab Enterprise Edition (EE) versions 17.10 through 18.3.4
• GitLab CE/EE versions 18.4.0 through 18.4.2
• GitLab CE/EE version 18.5.0

Discovery Timeline

• 2025-10-22 - GitLab releases security patch in version 18.5.1
• 2025-10-27 - CVE-2025-10497 published to NVD
• 2025-10-27 - Last updated in NVD database

Technical Details for CVE-2025-10497

Vulnerability Analysis

This vulnerability stems from improper resource allocation handling within GitLab CE/EE. When the application processes specially crafted payloads, it fails to implement adequate limits on resource consumption, allowing attackers to exhaust server resources and cause a denial of service condition.

The attack can be executed remotely over the network without requiring any authentication or user interaction, significantly lowering the barrier to exploitation. The vulnerability specifically impacts the availability of the GitLab service while confidentiality and integrity remain unaffected.

Organizations running vulnerable GitLab instances are at risk of complete service unavailability, which can severely impact development operations, CI/CD pipelines, and team collaboration capabilities.

Root Cause

The root cause of CVE-2025-10497 is related to CWE-770: Allocation of Resources Without Limits or Throttling. The application does not properly constrain resource allocation when handling certain types of input data. This allows malicious actors to craft payloads that trigger excessive resource consumption, whether through memory allocation, CPU utilization, or other system resources.

Without proper limits in place, the system cannot defend against resource exhaustion attacks, making it vulnerable to denial of service conditions when processing adversarial input.

Attack Vector

The attack vector for this vulnerability is network-based, allowing remote exploitation without authentication. An attacker can send specially crafted payloads to the vulnerable GitLab instance over the network. The attack does not require any privileges or user interaction to execute successfully.

The exploitation methodology involves:

1. Identifying a vulnerable GitLab CE/EE instance exposed to the network
2. Crafting malicious payloads designed to trigger resource exhaustion
3. Sending the payloads to the target system
4. The system processes the payloads without proper resource limits, leading to exhaustion
5. Service becomes unavailable to legitimate users

Technical details regarding the specific payload structure can be found in the HackerOne Security Report and GitLab Issue Discussion.

Detection Methods for CVE-2025-10497

Indicators of Compromise

• Unexpected spikes in CPU or memory utilization on GitLab servers
• GitLab services becoming unresponsive or timing out
• Unusual patterns in network traffic targeting GitLab endpoints
• System logs showing resource exhaustion errors or out-of-memory conditions
• Increased error rates in GitLab application logs

Detection Strategies

• Monitor GitLab server resource utilization (CPU, memory, disk I/O) for abnormal patterns
• Implement network-level monitoring to detect unusual traffic volumes or patterns targeting GitLab services
• Configure alerting for GitLab service health checks and availability
• Review application logs for repeated requests from single sources or unusual payload characteristics

Monitoring Recommendations

• Enable comprehensive logging for GitLab services and configure log aggregation
• Set up automated alerts for resource utilization thresholds exceeding normal baselines
• Implement rate limiting and traffic analysis at the network perimeter
• Deploy application performance monitoring (APM) tools to track GitLab response times and error rates

How to Mitigate CVE-2025-10497

Immediate Actions Required

• Upgrade GitLab CE/EE to version 18.5.1 or later immediately
• For version 18.4.x installations, upgrade to 18.4.3 or later
• For version 18.3.x and earlier installations, upgrade to 18.3.5 or later
• Implement network-level rate limiting to reduce the impact of potential exploitation attempts
• Monitor GitLab servers for signs of denial of service attacks

Patch Information

GitLab has released security patches addressing this vulnerability. The fixed versions are:

• GitLab 18.5.1 (for 18.5.x branch)
• GitLab 18.4.3 (for 18.4.x branch)
• GitLab 18.3.5 (for 18.3.x and earlier branches)

Organizations should upgrade to the latest patched version appropriate for their deployment. Full patch details are available in the GitLab Release Patch Note.

Workarounds

• Implement web application firewall (WAF) rules to filter potentially malicious payloads
• Configure network-level rate limiting to restrict the frequency of requests to GitLab endpoints
• Restrict network access to GitLab instances to trusted IP ranges where possible
• Deploy GitLab behind a reverse proxy with request size and rate limits configured

# Example nginx rate limiting configuration for GitLab
# Add to nginx configuration
limit_req_zone $binary_remote_addr zone=gitlab_ratelimit:10m rate=10r/s;

server {
    location / {
        limit_req zone=gitlab_ratelimit burst=20 nodelay;
        proxy_pass http://gitlab_backend;
    }
}