GHSA-cg4f-cq8h-3ch8 is a low-severity (CVSS 3.8) Cross-site Scripting (XSS) vulnerability in yeswiki/yeswiki. A fix is available for yeswiki/yeswiki — see the affected versions and patch details below.
Yeswiki Vulnerable to Authenticated Reflected Cross-site Scripting
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-cg4f-cq8h-3ch8.
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-cg4f-cq8h-3ch8 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 379,145 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
yeswiki/yeswikiReal-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
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 | 4.5.4composer require yeswiki/yeswiki:^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, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
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 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like GHSA-cg4f-cq8h-3ch8 can be triaged on real exposure rather than presence alone.
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 Security finds GHSA-cg4f-cq8h-3ch8 across Packagist dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.