CheckUser Extension up to 1.39.12/1.42.6/1.43.1 on Mediawiki Special:Investigate Interface cross site scripting

Summaryinfo

A vulnerability marked as problematic has been reported in CheckUser Extension up to 1.39.12/1.42.6/1.43.1 on Mediawiki. This affects an unknown function of the component Special:Investigate Interface. This manipulation causes cross site scripting. This vulnerability is registered as CVE-2025-53478. Remote exploitation of the attack is possible. No exploit is available. It is suggested to upgrade the affected component.

Detailsinfo

A vulnerability classified as problematic was found in CheckUser Extension up to 1.39.12/1.42.6/1.43.1 on Mediawiki. Affected by this vulnerability is an unknown code of the component Special:Investigate Interface. The manipulation 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. The summary by CVE is:

The CheckUser extension’s Special:Investigate interface is vulnerable to reflected XSS due to improper escaping of certain internationalized system messages rendered on the “IPs and User agents” tab. This issue affects Mediawiki - CheckUser 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.

It is possible to read the advisory at phabricator.wikimedia.org. This vulnerability is known as CVE-2025-53478 since 06/30/2025. The exploitation appears to be easy. The attack can be launched remotely. The exploitation doesn't need any form of authentication. It demands that the victim is doing some kind of user interaction. The technical details are unknown and an exploit is not publicly available. The attack technique deployed by this issue is T1059.007 according to MITRE ATT&CK.

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-2025-20294). Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.

Productinfo

Name

• CheckUser 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

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CPE 2.2info

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Entryinfo

Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.

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