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.
References (2)
Core 2
Core References
Issue Tracking
https://phabricator.wikimedia.org/T394692
Scores
CVSS v3
5.4
EPSS
0.0017
EPSS Percentile
6.7%
Attack Vector
NETWORK
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N
CISA SSVC
Vulnrichment
Exploitation
none
Automatable
no
Technical Impact
partial
Details
CWE
CWE-79
Status
published
Products (3)
Wikimedia Foundation/Mediawiki - CheckUser extension
1.39.x - 1.39.13
Wikimedia Foundation/Mediawiki - CheckUser extension
1.42.x - 1.42.7
Wikimedia Foundation/Mediawiki - CheckUser extension
1.43.x - 1.43.2
Published
Jul 07, 2025
Tracked Since
Feb 18, 2026