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OpenAdvisories
Medium · 5.4 CVE-2025-53478 EUVD-2025-20294GHSA-r979-wmj9-cr9m

CheckUser: Reflected Cross-Site Scripting (XSS) in Special:Investigate via unsanitized i18n messages

Published Jul 7, 2025 · Updated Jul 7, 2025 · Assigned by wikimedia-foundation

Description

The CheckUser extension’s Special:Investigate interface is vulnerable to reflected XSS due to improper escaping of certain internationalized system messages rendered on the “IPs and User agents” tab.

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.

Affected products

VendorProductAffectedFixed
Wikimedia Foundation Mediawiki - CheckUser extension 1.39.x – < 1.39.13, 1.42.x – < 1.42.7, 1.43.x – < 1.43.2 1.39.13

Advisories 1

References