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.
History

Mon, 07 Jul 2025 20:15:00 +0000

Type Values Removed Values Added
Metrics cvssV3_1

{'score': 5.4, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N'}

ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'poc', 'Technical Impact': 'partial'}, 'version': '2.0.3'}


Mon, 07 Jul 2025 15:15:00 +0000

Type Values Removed Values Added
Description 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.
Title WikiCategoryTagCloud: Reflected Cross-Site Scripting (XSS) via linkstyle attribute in parser function
Weaknesses CWE-79
References

cve-icon MITRE

Status: PUBLISHED

Assigner: wikimedia-foundation

Published: 2025-07-07T15:07:44.875Z

Updated: 2025-07-07T19:15:02.740Z

Reserved: 2025-06-30T15:20:44.462Z

Link: CVE-2025-53486

cve-icon Vulnrichment

Updated: 2025-07-07T19:13:14.209Z

cve-icon NVD

Status : Received

Published: 2025-07-07T15:15:27.947

Modified: 2025-07-07T20:15:27.460

Link: CVE-2025-53486

cve-icon Redhat

No data.