CVE-2025-53479CWE-79

CheckUser: Reflected Cross-Site Scripting (XSS) in Special:CheckUser via unsanitized internationalized message

Medium · published July 8, 2025

CVSS v3.1
5.4
EPSS
0%
Percentile
9.1
In the wild
Unconfirmed
What it is

The CheckUser extension’s Special:CheckUser interface is vulnerable to reflected XSS via the rev-deleted-user message. This message is rendered without proper escaping, making it possible to inject JavaScript through the uselang=x-xss language override mechanism.

This issue affects Mediawiki - CheckUser extension: from 1.42.X before 1.42.7, from 1.43.X before 1.43.2.

The record
Technical detail
CVSS v3.1
5.4 · MEDIUM
Vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N
CVSS v4.0
Not supplied
EPSS
0.00198 · 9.1th percentile
Weakness
CWE-79 · Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
Published
2025-07-08T17:16Z
EPSS history
Timeline
  • 08 JUL 17:16Z
    CheckUser: Reflected Cross-Site Scripting (XSS) in Special:CheckUser via unsanitized internationalized message
    cvelistv5