CVE-2025-53486 WikiCategoryTagCloud: Reflected Cross-Site Scripting (XSS) via linkstyle attribute in parser function
Reflected XSS in WikiCategoryTagCloud allows attackers to execute arbitrary JavaScript via the linkstyle attribute when victims hover over links.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- A user has to click or open something
- Fix
- None listed
What is CVE-2025-53486?
CVE-2025-53486 is a medium-severity cross-site scripting vulnerability in Wikimedia Foundation Mediawiki - WikiCategoryTagCloud extension, published on 7 Jul 2025. Any signed-in user can exploit it over the network, and only if a user opens a file or follows a link.
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.
Weakness: CWE-79
Which versions are affected by CVE-2025-53486?
How do I fix CVE-2025-53486?
No fix has been published for CVE-2025-53486 yet. Limit exposure of the affected software until one is available.
Escape output for the context it lands in and set a strict Content Security Policy. Upgrading the affected component is the real fix. More about Cross-site scripting.
Is CVE-2025-53486 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2025-53486 exists.
Sources
Also known as GHSA-p6wr-jj4q-jc36.