The CheckUser extension’s Special:Investigate page has a vulnerability in the Account information tab, where specific internationalized messages are rendered without proper escaping. Attackers can exploit this by appending ?uselang=x-xss to the URL, causing reflected XSS when the UI renders affected message keys.
This issue affects Mediawiki - CheckUser extension: from 1.39.X before 1.39.13, from 1.42.X before 1.42.7, from 1.43.X before 1.43.2.
CVSS Details
- CVSS 3.1 Base Score: 5.4
- CVSS 3.1 Vector: (CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N)
Prioritise with Active Threat Intelligence
With curated Threat Intelligence, you can see which vulnerabilities truly put you at risk, prioritize what matters most, and act before attackers do.
Explore Intelligence Hub