# 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.

- **Severity:** Not scored
- **Exploited in the wild:** Not known
- **Login needed:** An administrator
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 3 Feb 2026
- **Updated:** 3 Feb 2026
- **Also known as:** GHSA-rq75-xpj3-jxm4

## 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 (Improper Neutralization of Input During Web Page Generation)

## Which versions are affected by CVE-2025-61651?

It affects 1 product.


Products: 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.

## 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](https://insights.sbomify.com/CVE-2015-2940/): Cross-site request forgery in n/a (medium 6.8)
- [CVE-2019-18611](https://insights.sbomify.com/CVE-2019-18611/): Information disclosure in n/a (medium 6.5)
- [CVE-2019-16529](https://insights.sbomify.com/CVE-2019-16529/): Information disclosure in n/a (medium 5.3)
- [CVE-2026-34090](https://insights.sbomify.com/CVE-2026-34090/): Suggested investigations: Handle suppressed usernames (medium 4.8)
- [CVE-2025-61658](https://insights.sbomify.com/CVE-2025-61658/): Special:GlobalContributions shows edits on wikis the viewer doesn't have access to (low 1.3)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2025-61651 and fix it if it is affected.

What it is: 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.
Exploitation: There is no known exploitation of CVE-2025-61651 in the wild and no public exploit code.

Affected product: Wikimedia Foundation CheckUser. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2025-61651/ (Markdown: https://insights.sbomify.com/CVE-2025-61651/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2025-61651
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2025-61651
- OSV: https://osv.dev/vulnerability/CVE-2025-61651

---
From sbomify Insights: https://insights.sbomify.com/CVE-2025-61651/
Summaries are generated and may contain mistakes; the official description above is the record.