CVE-2025-61651
Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.
NVD · uneditedImproper 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.
Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.
dbcve analysis · high confidenceA Cross-Site Scripting (XSS) vulnerability exists in the Wikimedia CheckUser extension's buildUserElement.js file. User-supplied input is not properly neutralized before being rendered in web pages, allowing malicious scripts to execute in the context of other users' browsers.
Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.
Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.
NVD · CPE data< 1.44.1CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.
From the vector- Attack vector
- Network
- Complexity
- Low
- Privileges
- None
- User interaction
- Required
- Scope
- Changed
- Confidentiality
- Low
- Integrity
- Low
- Availability
- None
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.
dbcve checksWork through these to decide whether this CVE applies to you.
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Check CheckUser extension versionLocate the CheckUser extension in your MediaWiki installations extensions/CheckUser directory and read the version from the composer.json, extension.json, or VERSION file. Alternatively, access Special:Version on your wiki to see the installed extension version.Affected if The installed version is lower than 1.44.1
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Verify buildUserElement.js file presenceNavigate to the extensions/CheckUser/modules/special/ directory and confirm the existence of the buildUserElement.js file.Affected if The file exists and the extension version is below 1.44.1
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Check if CheckUser extension is enabledReview your MediaWiki LocalSettings.php file for the line: wfLoadExtension( 'CheckUser' ); or check through the Special:Version admin page to confirm the extension is active.Affected if The extension is enabled and the version is below 1.44.1
Your environment is affected if the CheckUser extension is enabled and its installed version is below 1.44.1, exposing the vulnerable buildUserElement.js file.
Generated from the published advisory. Verify against your own configuration.
Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.
dbcve · scoped1.44.1
Upgrade CheckUser extension to version 1.44.1 or later, which contains the fix for proper input sanitization in the buildUserElement.js file.
CheckUser 1.44.1
- Update the CheckUser MediaWiki extension to version 1.44.1 or later using your extension management method (e.g., Composer, Git pull)
- Verify the update was successful by checking the extension version in Special:Version
- Clear any caching systems (e.g., parser cache, object cache) if applicable
Generated from the published advisory — verify against the referenced sources before acting.
- Consultation2.0 h
- Implementation3.0 h
- Testing3.0 h
- Review / QA2.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $2,800.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2025-61651 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2025-61651 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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- Version or environment caveats, and links to real fixes
- No weaponised exploit code, or anything meant to cause harm
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