CVE-2021-39918 : Security Advisory and Response

The CVE-2021-39918 vulnerability in GitLab allows unauthorized users to add comments to a vulnerability without proper access control.

Understanding CVE-2021-39918

This section provides an overview of the GitLab vulnerability CVE-2021-39918.

What is CVE-2021-39918?

CVE-2021-39918 is an Incorrect Authorization vulnerability in GitLab EE affecting versions between 11.1 and 14.5.2. It enables users to add comments to a vulnerability that they should not access.

The Impact of CVE-2021-39918

The impact of this vulnerability is rated as LOW based on the CVSSv3.1 scoring system. It has a base score of 3.1, indicating a low severity level.

Technical Details of CVE-2021-39918

This section delves into the technical aspects of the CVE-2021-39918 vulnerability.

Vulnerability Description

The vulnerability stems from incorrect authorization controls in GitLab EE, leading to unauthorized comment additions to vulnerabilities.

Affected Systems and Versions

Product: GitLab
Vendor: GitLab
Versions Affected:
=11.1, <14.3.6

=14.4, <14.4.4

=14.5, <14.5.2

Exploitation Mechanism

The vulnerability allows users with low privileges to bypass access controls and add comments to vulnerabilities, potentially leading to unauthorized information sharing.

Mitigation and Prevention

Learn about the steps to address and prevent the CVE-2021-39918 vulnerability.

Immediate Steps to Take

Upgrade GitLab instances to versions above 14.3.6, 14.4.4, or 14.5.2, where the issue is fixed.
Monitor and restrict user permissions to prevent unauthorized comments.

Long-Term Security Practices

Regularly review and adjust access controls to ensure proper authorization.
Educate users on secure commenting practices to avoid inadvertent data exposure.

Patching and Updates

Stay informed on GitLab security advisories and apply patches promptly to address known vulnerabilities.