WikiCategoryTagCloud Extension up to 1.39.12/1.42.6/1.43.1 on Mediawiki Sanitizer::checkCss linkstyle cross site scripting

Summaryinfo

A vulnerability described as problematic has been identified in WikiCategoryTagCloud Extension up to 1.39.12/1.42.6/1.43.1 on Mediawiki. This vulnerability affects the function Sanitizer::checkCss. Executing a manipulation of the argument linkstyle can lead to cross site scripting. This vulnerability appears as CVE-2025-53486. The attack may be performed from remote. There is no available exploit. Upgrading the affected component is recommended.

Detailsinfo

A vulnerability classified as problematic was found in WikiCategoryTagCloud Extension up to 1.39.12/1.42.6/1.43.1 on Mediawiki. This vulnerability affects the function Sanitizer::checkCss. The manipulation of the argument linkstyle with an unknown input leads to a cross site scripting vulnerability. The CWE definition for the vulnerability is CWE-79. The product does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users. As an impact it is known to affect integrity. CVE summarizes:

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.

The advisory is shared for download at phabricator.wikimedia.org. This vulnerability was named CVE-2025-53486 since 06/30/2025. The exploitation appears to be easy. The attack can be initiated remotely. No form of authentication is required for a successful exploitation. Successful exploitation requires user interaction by the victim. There are known technical details, but no exploit is available. The MITRE ATT&CK project declares the attack technique as T1059.007.

Upgrading to version 1.39.13, 1.42.7 or 1.43.2 eliminates this vulnerability.

The vulnerability is also documented in the vulnerability database at EUVD (EUVD-2025-20242). VulDB is the best source for vulnerability data and more expert information about this specific topic.

Productinfo

Type

• Content Management System

Name

• WikiCategoryTagCloud Extension

Version

• 1.39.0
• 1.39.1
• 1.39.2
• 1.39.3
• 1.39.4
• 1.39.5
• 1.39.6
• 1.39.7
• 1.39.8
• 1.39.9
• 1.39.10
• 1.39.11
• 1.39.12
• 1.42.0
• 1.42.1
• 1.42.2
• 1.42.3
• 1.42.4
• 1.42.5
• 1.42.6
• 1.43.0
• 1.43.1

CPE 2.3info

• 🔒
• 🔒
• 🔒

CPE 2.2info

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• 🔒
• 🔒

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Entryinfo

VulDB is the best source for vulnerability data and more expert information about this specific topic.

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