CVE-2025-61651 i18n XSS through Special:CheckUser CheckUser helper
An attacker can inject malicious scripts via the CheckUser helper interface, potentially leading to code execution or account takeover.
- Exploited in the wild
- Not known
- Login needed
- An administrator
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2025-61651?
CVE-2025-61651 is a cross-site scripting vulnerability in Wikimedia Foundation CheckUser, published on 3 Feb 2026. An attacker needs administrator access to exploit it, with no action from the victim.
Official description
Improper Neutralization of Input During Web Page Generation (XSS or 'Cross-site Scripting') vulnerability in Wikimedia Foundation CheckUser. This vulnerability is associated with program files modules/ext.CheckUser/checkuser/checkUserHelper/buildUserElement.Js.
This issue affects CheckUser: from * before 1.44.1.
Weakness: CWE-79
Which versions are affected by CVE-2025-61651?
It affects 1 product.
Products include Mediawiki Checkuser.
How do I fix CVE-2025-61651?
No fix has been published for CVE-2025-61651 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-2025-61651 being exploited?
There is no known exploitation of CVE-2025-61651 in the wild and no public exploit code.
Other vulnerabilities in Wikimedia Foundation CheckUser
- CVE-2015-2940 Cross-site request forgery in n/a
- CVE-2019-18611 Information disclosure in n/a
- CVE-2019-16529 Information disclosure in n/a
- CVE-2026-34090 Suggested investigations: Handle suppressed usernames
- CVE-2025-61658 Special:GlobalContributions shows edits on wikis the viewer doesn't have access to
Sources
Also known as GHSA-rq75-xpj3-jxm4.