CVE-2021-39908 : Security Advisory and Response

In August 2021, GitLab discovered a vulnerability in its versions that allowed the abuse of certain Unicode characters for injecting malicious code unnoticed within the projects.

Understanding CVE-2021-39908

CVE-2021-39908 is a code injection vulnerability in GitLab versions that could lead to the injection of malicious code using specific Unicode characters.

What is CVE-2021-39908?

GitLab versions from 0.8.0 to 14.2.6, 14.3 to 14.3.4, and 14.4 to 14.4.1 are susceptible to code injection via Unicode characters.

The Impact of CVE-2021-39908

The vulnerability has a CVSS v3.1 base score of 6.5 (Medium severity) due to the potential high integrity impact allowing attackers to inject code.

Technical Details of CVE-2021-39908

The technical details of the vulnerability provide insights into how it can be exploited.

Vulnerability Description

Improper control of code generation in GitLab can lead to code injection using Unicode characters.

Affected Systems and Versions

GitLab versions from 0.8.0 to 14.2.6, 14.3 to 14.3.4, and 14.4 to 14.4.1.

Exploitation Mechanism

Attackers abuse specific Unicode characters to inject malicious code without detection in the project UI.

Mitigation and Prevention

Following best practices can help in mitigating and preventing the exploitation of this vulnerability.

Immediate Steps to Take

Upgrade GitLab to versions 14.2.6, 14.3.4, or 14.4.1 to address the vulnerability.
Disable unidentified Unicode characters usage in the project settings.

Long-Term Security Practices

Regularly monitor GitLab logs for unusual code injection activities.
Educate developers and users on secure coding practices to prevent code injection.

Patching and Updates

Stay informed about security updates from GitLab and apply patches promptly to protect against vulnerabilities.