CVE-2025-53480

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.

Score

CVSS 3.1 5.4 Medium

Status

Deferred - c4f26cc8-17ff-4c99-b5e2-38fc1793eacc

Published

2025-07-08

Last modified

2025-07-08

Weaknesses

CWE-79

Affected products

• Mediawiki - Checkuser Extension (Wikimedia Foundation)

References

• https://gerrit.wikimedia.org/r/q/I777fc55fef15c3b00df0db268af2b64cb2d6e381
• https://phabricator.wikimedia.org/T394700