CVE-2021-39916 Explained : Impact and Mitigation

In this article, we will delve into the details of CVE-2021-39916, a vulnerability affecting GitLab versions that allowed unauthorized access to certain features.

Understanding CVE-2021-39916

This section provides an overview of the vulnerability and its impact on GitLab systems.

What is CVE-2021-39916?

CVE-2021-39916 is characterized by a lack of access control check in GitLab's External Status Check feature, enabling authenticated users to retrieve configurations from versions 14.1 to 14.5.2.

The Impact of CVE-2021-39916

The vulnerability poses a medium severity threat with a CVSS base score of 4.3. Here are the key impacts:

Attack Complexity: Low
Attack Vector: Network
Confidentiality Impact: Low
Integrity Impact: None
Privileges Required: Low
User Interaction: None
Scope: Unchanged
Availability Impact: None

Technical Details of CVE-2021-39916

This section covers the technical aspects of the vulnerability.

Vulnerability Description

The flaw allowed any authenticated user to access configurations of External Status Check in affected GitLab versions.

Affected Systems and Versions

Affected product and versions:

Product: GitLab
Versions: >=14.1, <14.3.6; >=14.4, <14.4.4; >=14.5, <14.5.2

Exploitation Mechanism

The vulnerability could be exploited by an authenticated user to retrieve configurations without proper access control checks.

Mitigation and Prevention

Explore the measures to mitigate the risks associated with CVE-2021-39916.

Immediate Steps to Take

Upgrade GitLab to version 14.3.6, 14.4.4, or 14.5.2 to eliminate the vulnerability.
Monitor configurations for unauthorized changes.

Long-Term Security Practices

Implement proper access control mechanisms.
Regularly audit and review user access levels.
Educate users on security best practices.

Patching and Updates

Stay updated with GitLab's security advisories and promptly apply patches.