CVE-2021-22251 Explained : Impact and Mitigation

This article provides details about CVE-2021-22251, a vulnerability affecting GitLab versions that allowed projects to add members with email addresses that should be blocked by group settings.

Understanding CVE-2021-22251

CVE-2021-22251 is a vulnerability in GitLab that arises from improper validation of invited users' email addresses, impacting all versions since 12.2.

What is CVE-2021-22251?

The vulnerability in GitLab EE allowed projects to add members using email addresses from domains that should have been blocked based on group settings.

The Impact of CVE-2021-22251

With a CVSS v3.1 base score of 4.3 (Medium severity), the vulnerability could be exploited with low privileges required and could compromise the integrity of affected systems without impacting confidentiality or availability.

Technical Details of CVE-2021-22251

The technical details of this CVE include:

Vulnerability Description

The vulnerability stemmed from improper input validation in GitLab, enabling the addition of members with restricted email domains.

Affected Systems and Versions

GitLab versions >=12.2 and <13.12.9, >=14.0 and <14.0.7, and >=14.1 and <14.1.2 were impacted by this vulnerability.

Exploitation Mechanism

The vulnerability could be exploited over a network with low attack complexity and user interaction, requiring low privileges.

Mitigation and Prevention

To mitigate the risks associated with CVE-2021-22251, consider the following:

Immediate Steps to Take

Update GitLab to versions that contain patches addressing the vulnerability.
Review and adjust group settings to restrict email domains effectively.

Long-Term Security Practices

Conduct regular security assessments and audits of GitLab installations.
Educate users on secure invitation practices and email domain restrictions.

Patching and Updates

Stay informed about security updates and patches released by GitLab to address vulnerabilities like CVE-2021-22251.