CVE-2021-39945 : What You Need to Know

A vulnerability in GitLab affects various versions, allowing unauthorized approval of Merge Requests despite access restrictions.

Understanding CVE-2021-39945

GitLab's API vulnerability permits bypassing access controls for approving Merge Requests, impacting specified versions.

What is CVE-2021-39945?

The vulnerability in GitLab CE/EE API allows project authors to approve Merge Requests even after access revocation, affecting designated version ranges.

The Impact of CVE-2021-39945

The vulnerability's impact is assessed as low severity with specific attack vector and privileges required for exploitation.

Technical Details of CVE-2021-39945

GitLab's vulnerability stems from improper access controls in its API, leading to unauthorized approval actions.

Vulnerability Description

The flaw allows Merge Request authors to approve despite revoked access, affecting GitLab versions specified in the CVE details.

Affected Systems and Versions

GitLab versions >=14.5 and <14.5.2
GitLab versions >=14.4 and <14.4.4
GitLab versions >=9.4 and <14.3.6

Exploitation Mechanism

Attack Complexity: Low
Privileges Required: High
Attack Vector: Network
Integrity Impact: Low

Mitigation and Prevention

Immediate measures and ongoing security practices help mitigate the risk and prevent exploitation.

Immediate Steps to Take

Update GitLab to versions >=14.5.2, >=14.4.4, or >=14.3.6 to eliminate the vulnerability.
Monitor and restrict access of project authors to prevent unauthorized actions.

Long-Term Security Practices

Regularly audit access controls and permissions within GitLab to ensure proper restrictions.
Educate users on secure practices and the importance of access management.

Patching and Updates

Stay informed about security patches and updates released by GitLab to address vulnerabilities promptly.