CVE-2021-39946 Explained : Impact and Mitigation

This CVE-2021-39946 article provides details about a vulnerability affecting GitLab versions 14.3 to 14.3.6, 14.4 to 14.4.4, and 14.5 to 14.5.2 allowing XSS exploitation.

Understanding CVE-2021-39946

CVE-2021-39946 is a security vulnerability found in GitLab versions mentioned above, impacting the generation of HTML code related to emojis.

What is CVE-2021-39946?

The vulnerability is due to improper neutralization of user input, enabling attackers to exploit cross-site scripting (XSS) by manipulating HTML code.

The Impact of CVE-2021-39946

The vulnerability is rated with a CVSS base score of 8.7 (High severity) with significant impacts on confidentiality, integrity, and requiring low privileges for exploitation.

Technical Details of CVE-2021-39946

GitLab CVE-2021-39946 involves the following technical aspects:

Vulnerability Description

Affects GitLab versions 14.3 to 14.3.6, 14.4 to 14.4.4, and 14.5 to 14.5.2 by allowing attackers to execute XSS attacks through the manipulation of HTML code.

Affected Systems and Versions

Product: GitLab
Vendor: GitLab
Affected Versions:
=14.3, <14.3.6

=14.4, <14.4.4

=14.5, <14.5.2

Exploitation Mechanism

Attackers can abuse the vulnerability in GitLab's HTML code generation related to emojis to launch XSS attacks.

Mitigation and Prevention

To address CVE-2021-39946, follow these steps:

Immediate Steps to Take

Update GitLab to versions higher than 14.3.6, 14.4.4, and 14.5.2 to mitigate the vulnerability.
Monitor and validate user inputs to prevent malicious scripts.

Long-Term Security Practices

Conduct regular security trainings to educate personnel on secure coding practices.
Implement Content Security Policy (CSP) to reduce the impact of XSS attacks.

Patching and Updates

Apply security patches promptly as released by GitLab to address vulnerabilities and enhance system security.