CVE-2024-6826: GitLab CE/EE DOS Vulnerability

CVE-2024-6826 Overview

A denial of service vulnerability has been discovered in GitLab Community Edition (CE) and Enterprise Edition (EE) affecting all versions from 11.2. The vulnerability exists in the XML manifest import functionality, where a maliciously crafted XML file can be imported to cause a denial of service condition. This allows an authenticated attacker with low privileges to disrupt the availability of GitLab instances by exploiting improper resource allocation controls during the import process.

Critical Impact

Authenticated attackers can cause denial of service by importing maliciously crafted XML manifest files, potentially disrupting CI/CD pipelines and development workflows across the organization.

Affected Products

• GitLab Community Edition (CE) versions 11.2 to before 17.3.6
• GitLab Enterprise Edition (EE) versions 11.2 to before 17.3.6
• GitLab CE/EE versions 17.4 to before 17.4.3
• GitLab CE/EE version 17.5.0 (fixed in 17.5.1)

Discovery Timeline

• 2024-10-24 - CVE CVE-2024-6826 published to NVD
• 2024-12-13 - Last updated in NVD database

Technical Details for CVE-2024-6826

Vulnerability Analysis

This vulnerability is classified under CWE-770 (Allocation of Resources Without Limits or Throttling). The flaw resides in GitLab's XML manifest import functionality, which fails to properly validate and limit resource consumption when processing XML files. When an attacker submits a specially crafted XML manifest file, the parsing operation can consume excessive system resources, leading to service degradation or complete unavailability.

The attack requires network access and low-privilege authentication to the GitLab instance. While user interaction is not required for exploitation, the attacker must have permission to import manifests. The vulnerability impacts only availability—there is no impact on confidentiality or integrity of data.

Root Cause

The root cause is improper resource allocation controls in the XML parsing functionality. GitLab's import feature does not adequately limit the computational resources that can be consumed during XML manifest processing. This allows malformed or excessively complex XML structures to trigger resource exhaustion conditions, potentially affecting the entire GitLab instance.

Attack Vector

The attack is network-based and requires an authenticated user to submit a malicious XML manifest file through GitLab's import functionality. The vulnerability can be exploited by:

1. An attacker authenticating to a vulnerable GitLab instance with minimal privileges
2. Crafting a malicious XML manifest file designed to exhaust system resources
3. Submitting the malicious file through the import mechanism
4. The server processes the file without proper resource limits, causing denial of service

The attack does not require user interaction beyond the attacker's own actions, and the scope remains unchanged (the vulnerability does not allow the attacker to affect resources beyond the vulnerable component).

Detection Methods for CVE-2024-6826

Indicators of Compromise

• Unusual spikes in CPU or memory usage on GitLab servers during import operations
• Abnormally large or complex XML files submitted through the manifest import feature
• Failed or slow import operations accompanied by system resource exhaustion
• Multiple import requests from the same user in a short time period

Detection Strategies

• Monitor GitLab server resource utilization for anomalous patterns during import operations
• Implement file size and complexity checks on uploaded XML manifest files
• Review GitLab audit logs for unusual import activity patterns
• Set up alerts for import operations that exceed normal processing time thresholds

Monitoring Recommendations

• Configure infrastructure monitoring to alert on sustained high CPU/memory usage
• Enable detailed logging for GitLab import operations to capture anomalous file submissions
• Implement rate limiting on import endpoints to detect potential exploitation attempts
• Review the GitLab Issue #472928 for additional monitoring guidance

How to Mitigate CVE-2024-6826

Immediate Actions Required

• Upgrade GitLab CE/EE to version 17.3.6, 17.4.3, or 17.5.1 or later immediately
• Review recent import operations for potentially malicious activity
• Consider temporarily restricting access to the manifest import feature if patching cannot be performed immediately
• Monitor system resources closely until the patch is applied

Patch Information

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

• GitLab CE/EE 17.3.6 or later for the 17.3.x branch
• GitLab CE/EE 17.4.3 or later for the 17.4.x branch
• GitLab CE/EE 17.5.1 or later for the 17.5.x branch

For detailed patch information and upgrade instructions, refer to the HackerOne Report #2571364 and the GitLab Issue #472928.

Workarounds

• Restrict manifest import permissions to trusted users only until patching is complete
• Implement web application firewall (WAF) rules to limit XML file sizes on import endpoints
• Configure resource limits (CPU/memory) for GitLab worker processes handling imports
• Monitor and alert on import operations that exceed normal resource consumption thresholds

# Example: Restrict import permissions via GitLab Rails console
# Access the Rails console
gitlab-rails console

# Disable project import for non-admin users (temporary workaround)
# ApplicationSetting.current.update(import_sources: [])