MediaWiki Cross-site Scripting vulnerabilityGHSA-fmrf-p77g-vv5c
MEDIUMGHSA-fmrf-p77g-vv5c is a medium-severity (CVSS 6.1) Cross-site Scripting (XSS) vulnerability in wikibase/wikibase. 1 public exploit or proof-of-concept reference is indexed, so weaponization risk is real. The records list no fixed version yet; check the vendor advisory below and apply the mitigations in the meantime.
Exploitation Status
Proof-of-concept exploit code exists
- CISA’s SSVC triage found public proof-of-concept exploit code for this CVE, though no confirmed active exploitation.
Exploitation and automatability from CISA’s SSVC triage for GHSA-fmrf-p77g-vv5c.
EPSS Exploitation Probability
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
How urgent is this, really
Where this sits among everything scored
Real-World Exposure
wikibase/wikibaseReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects Packagist packages — download data is not available via public APIs for these ecosystems.
Description
An issue was discovered in SiteLinksView.php in Wikibase in MediaWiki through 1.39.3. There is XSS via a crafted badge title attribute. This is also related to lack of escaping in wbTemplate (from resources/wikibase/templates.js) for quotes (which can be in a title attribute).
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐘Packagist | wikibase/wikibase | all versions | No fix |
Affected Products
mediawikimediawikiResearch use only. For defensive security, authorized penetration testing, and academic research only. Never execute exploit code against systems without explicit written authorization.
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for wikibase/wikibase, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Remediation status
The records we use list no patched version of wikibase/wikibase for GHSA-fmrf-p77g-vv5c. Check the maintainer's advisory, and where your build allows, override or pin the dependency away from the vulnerable range.
Mitigate without a patch
Escape or sanitise the affected output on the server side rather than relying on client-side filtering, and add a Content-Security-Policy that blocks inline script execution so injected markup cannot run even if it reaches the page.
Frequently Asked Questions
Is GHSA-fmrf-p77g-vv5c in your dependencies?
Find it across Packagist, including transitive dependencies.