GHSA-pj42-r64f-4xfq is a low-severity (CVSS 2) Cross-site Scripting (XSS) vulnerability in concrete5/concrete5. O3 Security confirms whether GHSA-pj42-r64f-4xfq is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
Concrete CMS Stored XSS on the calendar color settings screen
Real-World Exposure
concrete5/concrete5🐘concrete5/concrete5Real-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
Concrete CMS version 9 before 9.2.8 and previous versions prior to 8.5.16 is vulnerable to Stored XSS on the calendar color settings screen since Information input by the user is output without escaping. A rogue administrator could inject malicious javascript into the Calendar Color Settings screen which might be executed when users visit the affected page. The Concrete CMS security team gave this vulnerability a CVSS v3.1 score of 2.0 with a vector of AV:N/AC:H/PR:H/UI:R/S:U/C:L/I:N/A:N&version=3.1 https://nvd.nist.gov/vuln-metrics/cvss/v3-calculator
Thank you Rikuto Tauchi for reporting
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐘Packagist | concrete5/concrete5 | ≥ 9.0.0RC1&&< 9.2.8 | 9.2.8 |
| 🐘Packagist | concrete5/concrete5 | all versions | 8.5.16 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for concrete5/concrete5. 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 concrete5/concrete5 to 9.2.8 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-pj42-r64f-4xfq 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-pj42-r64f-4xfq 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-pj42-r64f-4xfq. 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-pj42-r64f-4xfq in your dependencies?
O3 detects GHSA-pj42-r64f-4xfq across Packagist dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.