CVE-2021-41798 : Security Advisory and Response

MediaWiki before 1.36.2 allows XSS due to unescaped month related messages on the Special:Search results page.

Understanding CVE-2021-41798

What is CVE-2021-41798?

MediaWiki version prior to 1.36.2 is vulnerable to a Cross-Site Scripting (XSS) issue where month-related messages are not properly escaped on the Special:Search results page.

The Impact of CVE-2021-41798

This vulnerability could allow an attacker to execute malicious scripts in the context of an unsuspecting user's web session, potentially leading to various attacks such as stealing sensitive information or performing unauthorized actions on behalf of the user.

Technical Details of CVE-2021-41798

Vulnerability Description

The XSS vulnerability in MediaWiki before version 1.36.2 is a result of unescaped month-related messages displayed on the Special:Search results page.

Affected Systems and Versions

Vendor: n/a
Product: n/a
Versions: All versions before 1.36.2 are affected.

Exploitation Mechanism

The issue arises from the lack of proper escaping of month-related messages, which allows an attacker to inject and execute malicious scripts in the user's browser.

Mitigation and Prevention

Immediate Steps to Take

Upgrade MediaWiki to version 1.36.2 or later to mitigate the XSS vulnerability.
Regularly monitor and review user-generated content for any suspicious scripts or payloads.

Long-Term Security Practices

Implement input validation and output encoding to prevent XSS attacks.
Provide security training to developers on secure coding practices to avoid similar vulnerabilities.

Patching and Updates

Stay informed about security advisories and promptly apply patches released by the vendor.