GHSA-wcx3-63mm-h8x6 is a medium-severity (CVSS 6.1) Cross-site Scripting (XSS) vulnerability in samwilson/unlinked-wikibase. A fix is available for samwilson/unlinked-wikibase — see the affected versions and patch details below.
MediaWiki UnlinkedWikibase Cross-site Scripting vulnerability
Exploitation Status
No confirmed exploitation observed yet
- CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.
Exploitation and automatability from CISA’s SSVC triage for GHSA-wcx3-63mm-h8x6.
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
How urgent is this, really
GHSA-wcx3-63mm-h8x6 plotted by exploitation likelihood (EPSS) against impact (CVSS). The shaded corner — EPSS 50%+ and CVSS 7.0+ — is where this CVE doesn't sit, though severity or exploitability alone can still warrant action.
Where this sits among everything scored
Of 377,238 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Real counts from FIRST.org, not a sample — log-scaled since the landscape is heavily right-skewed.
Real-World Exposure
samwilson/unlinked-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 the UnlinkedWikibase extension in MediaWiki before 1.42.0. XSS can occur through an interface message. Error messages (in the $err var) are not escaped before being passed to Html::rawElement() in the getError() function in the Hooks class.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐘Packagist | samwilson/unlinked-wikibase | all versions | 1.42.0composer require samwilson/unlinked-wikibase:^1.42.0 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for samwilson/unlinked-wikibase, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update samwilson/unlinked-wikibase to 1.42.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-wcx3-63mm-h8x6 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like GHSA-wcx3-63mm-h8x6 can be triaged on real exposure rather than presence alone.
Tailored to GHSA-wcx3-63mm-h8x6. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is GHSA-wcx3-63mm-h8x6 in your dependencies?
O3 Security finds GHSA-wcx3-63mm-h8x6 across Packagist dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.