5.4

CVE-2025-53479: wikimedia foundation mediawiki - checkuser extension Cross-site Scripting

CVSS: 5.4v3.1MediumDeferred
Published 08-07-2025Last modified 10-07-2025
Open JSON

Vulnerability summary

CVE-2025-53479 is a medium (CVSS 5.4) Cross-site Scripting vulnerability in wikimedia foundation mediawiki - checkuser extension. EPSS estimates a 0.20% chance of exploitation in the next 30 days, higher than 9% of scored vulnerabilities.

Overall risk
22/100
0100
Low · default modelHow is this calculated?
CVSS score
5.4/10
010
Medium · v3.1 (CVE.org)
EPSS score
0.20%
0%100%
Low · +0.02 pp in 30 days
KEVNot listedIn no KEV catalog
RansomwareNone recordedNo known use recorded
Public exploits0No public exploits recorded

Timeline

  1. 08-07-2025
    PublishedVulnerability first disclosed.
  2. 10-07-2025
    Last modifiedVulnerability information updated.

Description

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.

CVSS metrics

2 scores · 2 sources · 1 version

EPSS trend

Probability

0.20%

Chance of exploitation in the next 30 days

Percentile

9%

Versus all other CVEs

30-day change

+0.02 pp

From 0.17% on 20-09-2026

20-09-202620-10-2026
EPSS score
0.20%

Known exploited

Compare KEV catalogs

Not in any of the 3 tracked catalogs.

Public exploits

0 found

No public exploits indexed.

Weaknesses

CWE · root cause

Affected systems

Wikimedia foundation1 product

1 vendor · 1 product

References

2 links