CVE-2021-39866 Explained : Impact and Mitigation

CVE-2021-39866 is a vulnerability in GitLab that allows persistent access via project access tokens.

Understanding CVE-2021-39866

This section provides an overview of the vulnerability.

What is CVE-2021-39866?

CVE-2021-39866 is a business logic error in the project deletion process in GitLab 13.6 and later, which enables persistent access via project access tokens.

The Impact of CVE-2021-39866

This section discusses the impact of the vulnerability.

The CVSSv3.1 base score for CVE-2021-39866 is 5.4, indicating a Medium severity vulnerability with low confidentiality and integrity impacts. The attack complexity is low, requiring low privileges and no user interaction, and the attack vector is through the network with no availability impact.

Technical Details of CVE-2021-39866

This section delves into the technical aspects of the vulnerability.

Vulnerability Description

The vulnerability stems from a business logic error in the project deletion process in GitLab, allowing persistent access via project access tokens.

Affected Systems and Versions

The following versions of GitLab are affected by CVE-2021-39866:

GitLab version >=14.3, <14.3.1
GitLab version >=14.2, <14.2.5
GitLab version >=13.6, <14.1.7

Exploitation Mechanism

The vulnerability can be exploited by malicious actors who can leverage the business logic error in the project deletion process to maintain unauthorized access through project access tokens.

Mitigation and Prevention

This section provides guidance on mitigating the impact of CVE-2021-39866.

Immediate Steps to Take

Upgrade GitLab to a non-vulnerable version.
Monitor project access tokens for unauthorized activity.

Long-Term Security Practices

Conduct regular security audits and penetration testing.
Educate users on secure coding practices and project management.

Patching and Updates

Apply patches released by GitLab to fix the business logic error in the project deletion process.