GHSA-4vr7-m8p8-434h
MEDIUMGHSA-4vr7-m8p8-434h is a medium-severity (CVSS 6.1) Cross-site Scripting (XSS) vulnerability in mediawiki/core. O3 Security confirms whether GHSA-4vr7-m8p8-434h is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
MediaWiki Cross-site Scripting (XSS) vulnerability
Real-World Exposure
mediawiki/core🐘mediawiki/core🐘mediawiki/coreReal-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
In MediaWiki before 1.31.9 and 1.32.x through 1.34.x before 1.34.3, XSS related to jQuery can occur. The attacker creates a message with [javascript:payload xss] and turns it into a jQuery object with mw.message().parse(). The expected result is that the jQuery object does not contain an <a> tag (or it does not have a href attribute, or it's empty, etc.). The actual result is that the object contains an <a href ="javascript... that executes when clicked.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐘Packagist | mediawiki/core | ≥ 1.31.0&&< 1.31.9 | 1.31.9 |
| 🐘Packagist | mediawiki/core | ≥ 1.32.0&&< 1.34.3 | 1.34.3 |
| 🐘Packagist | mediawiki/core | ≥ 1.35.0-rc.0&&< 1.35.0 | 1.35.0 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for mediawiki/core. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update mediawiki/core to 1.31.9 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-4vr7-m8p8-434h 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 pinpoints whether GHSA-4vr7-m8p8-434h is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.
Tailored to GHSA-4vr7-m8p8-434h. 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-4vr7-m8p8-434h in your dependencies?
O3 detects GHSA-4vr7-m8p8-434h across Packagist dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.