CVE-2021-39943 : Security Advisory and Response

A detailed overview of the GitLab authorization logic error vulnerability.

Understanding CVE-2021-39943

Exploring the impact, technical details, and mitigation steps for the CVE-2021-39943 vulnerability.

What is CVE-2021-39943?

An authorization logic error in the External Status Check API in GitLab EE allowed unauthorized status updates via API calls.

The Impact of CVE-2021-39943

The CVSS score for this vulnerability is 4.3 (Medium Severity). It could be exploited with low privileges and basic network access, impacting data integrity.

Technical Details of CVE-2021-39943

Details on the vulnerability, affected systems, and exploitation mechanisms.

Vulnerability Description

It affects GitLab versions starting from 14.1 before 14.3.6, 14.4 before 14.4.4, and 14.5 before 14.5.2, enabling unauthorized status updates.

Affected Systems and Versions

GitLab versions >=14.1.0, <14.3.6
GitLab versions >=14.4.0, <14.4.4
GitLab versions >=14.5.0, <14.5.2

Exploitation Mechanism

Low attack complexity and user privileges
Network-based attack vector

Mitigation and Prevention

Essential steps to secure systems and prevent exploitation.

Immediate Steps to Take

Apply GitLab patches for versions mentioned
Monitor API calls and verify user permissions

Long-Term Security Practices

Regular security audits and access reviews
Train users on secure API usage

Patching and Updates

Keep GitLab updated with the latest security patches and version releases.