Vulnerability · Published Jul 7, 2025 · Assigned by wikimedia-foundation
CVE-2025-53486WikiCategoryTagCloud: Reflected Cross-Site Scripting (XSS) via linkstyle attribute in parser function
Medium 5.4
In plain English
A medium-severity cross-site scripting in Mediawiki - WikiCategoryTagCloud extension from Wikimedia Foundation. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.3% (higher than 22% of all known vulnerabilities).
Official 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.
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| Wikimedia Foundation | Mediawiki - WikiCategoryTagCloud extension | 1.39.x – before 1.39.131.42.x – before 1.42.71.43.x – before 1.43.2 |
Weakness: CWE-79 · Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N