CVE-2021-42046 Explained : Impact and Mitigation

An issue was discovered in the GlobalWatchlist extension in MediaWiki through 1.36.2. The rev-deleted-user and ntimes messages were not properly escaped and allowed for users to inject HTML and JavaScript.

Understanding CVE-2021-42046

This CVE involves a security flaw in the GlobalWatchlist extension in MediaWiki version 1.36.2.

What is CVE-2021-42046?

The vulnerability allowed users to inject HTML and JavaScript through the rev-deleted-user and ntimes messages due to improper escaping.

The Impact of CVE-2021-42046

Attackers could potentially execute malicious scripts on the affected systems.
This could lead to unauthorized access to sensitive information and compromise the integrity of the system.

Technical Details of CVE-2021-42046

This section provides a deeper dive into the technical aspects of the vulnerability.

Vulnerability Description

The issue stemmed from improper handling of the rev-deleted-user and ntimes messages, enabling malicious injection of HTML and JavaScript.

Affected Systems and Versions

MediaWiki versions up to 1.36.2 are vulnerable to this exploit.

Exploitation Mechanism

Attackers could leverage the vulnerability to insert malicious code into the affected messages, leading to potential security breaches.

Mitigation and Prevention

It is crucial to take immediate action to address and prevent exploitation of this vulnerability.

Immediate Steps to Take

Upgrade MediaWiki to version 1.36.3 or later, where the issue has been patched.
Implement content security policies to restrict code execution within the application.

Long-Term Security Practices

Regularly audit and review extension code for security vulnerabilities.
Educate users on safe practices to prevent inadvertent execution of malicious scripts.

Patching and Updates

Stay vigilant for security updates and patches released by MediaWiki to ensure protection against known vulnerabilities.