CVE-2025-53486

Summary

The WikiCategoryTagCloud extension is vulnerable to reflected XSS via the linkstyle attribute, which is improperly concatenated into inline HTML without escaping. An attacker can inject JavaScript event handlers such as onmouseenter using carefully crafted input via the {{#tag:tagcloud}} parser function, resulting in arbitrary JavaScript execution when a victim hovers over a link in the category cloud.

The vulnerability exists because the linkstyle parameter is only passed through Sanitizer::checkCss() (which does not escape HTML) and is then directly inserted into a style attribute using string concatenation instead of Html::element or Html::openElement.

This issue affects Mediawiki - WikiCategoryTagCloud 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 Software

VendorProductVersion RangeStatus
Wikimedia FoundationMediawiki - WikiCategoryTagCloud extension1.39.x < 1.39.13affected
Wikimedia FoundationMediawiki - WikiCategoryTagCloud extension1.42.x < 1.42.7affected
Wikimedia FoundationMediawiki - WikiCategoryTagCloud extension1.43.x < 1.43.2affected

Weaknesses

  • CWE-79: CWE-79 Improper Neutralization of Input During Web Page Generation (XSS or 'Cross-site Scripting')

ADP Enrichment

CISA ADP Vulnrichment

  • SSVC:
  • Exploitation: poc
    • Automatable: no
    • Technical Impact: partial

References