GHSA-cg4f-cq8h-3ch8 is a low-severity (CVSS 3.8) Cross-site Scripting (XSS) vulnerability in yeswiki/yeswiki. O3 Security confirms whether GHSA-cg4f-cq8h-3ch8 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
Yeswiki Vulnerable to Authenticated Reflected Cross-site Scripting
Real-World Exposure
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Description
Summary
Vulnerable Version: Yeswiki < v4.5.4
Vulnerable Endpoint: /?PagePrincipale%2Fdeletepage
Vulnerable Parameter: incomingurl
Payload: "><script>alert(1)</script>
Details
Reflected Cross-Site Scripting (XSS) attacks are a type of injection, in which malicious scripts are injected into otherwise benign and trusted websites. XSS attacks occur when an attacker uses a web application to send malicious code, generally in the form of a browser-side script, to a different end user. Flaws that allow these attacks to succeed are quite widespread and occur anywhere a web application uses input from a user within the output it generates without validating or encoding it.
PoC
NOTE: This vulnerability requires admin access.
-
Visit the endpoint as mentioned below and see that an alert box pops up:
URL with Payload:
https://yeswiki.net/?PagePrincipale%2Fdeletepage&incomingurl="><script>alert(1)</script>
Impact
An attacker can use a reflected cross-site scripting attack to steal cookies from an authenticated user by having them click on a malicious link. Stolen cookies allow the attacker to take over the user’s session. This vulnerability may also allow attackers to deface the website or embed malicious content.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐘Packagist | yeswiki/yeswiki | all versions | 4.5.4 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for yeswiki/yeswiki. 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 yeswiki/yeswiki to 4.5.4 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-cg4f-cq8h-3ch8 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-cg4f-cq8h-3ch8 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-cg4f-cq8h-3ch8. 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-cg4f-cq8h-3ch8 in your dependencies?
O3 detects GHSA-cg4f-cq8h-3ch8 across Packagist dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.