GHSA-4gpr-p634-922x is a medium-severity (CVSS 6.6) Cross-site Scripting (XSS) vulnerability in contao/core-bundle. 1 public exploit or proof-of-concept reference is indexed, so weaponization risk is real. A fix is available for contao/core-bundle — see the affected versions and patch details below.
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-4gpr-p634-922x.
EPSS Exploitation Probability
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
How urgent is this, really
Where this sits among everything scored
Real-World Exposure
contao/core-bundle🐘contao/core-bundle🐘contao/core-bundleReal-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
Impact
Authenticated users can inject malicious code in widgets with units, which is then executed both in the element preview (back end) and on the website (front end).
Patches
Update to Contao 4.9.42, 4.13.28 or 5.1.10.
Workarounds
Disable login for all untrusted back end users.
References
https://contao.org/en/security-advisories/cross-site-scripting-in-widgets-with-units
For more information
If you have any questions or comments about this advisory, open an issue in contao/contao.
Credits
Thanks to Christian Pöschl and Fabian Brenner from usd AG for reporting this vulnerability.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐘Packagist | contao/core-bundle | ≥ 4.0.0&&< 4.9.42 | 4.9.42composer require contao/core-bundle:^4.9.42 |
| 🐘Packagist | contao/core-bundle | ≥ 4.10.0&&< 4.13.28 | 4.13.28composer require contao/core-bundle:^4.13.28 |
| 🐘Packagist | contao/core-bundle | ≥ 5.0.0&&< 5.1.10 | 5.1.10composer require contao/core-bundle:^5.1.10 |
Affected Products
contaocontaoResearch use only. For defensive security, authorized penetration testing, and academic research only. Never execute exploit code against systems without explicit written authorization.
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for contao/core-bundle, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update contao/core-bundle to 4.9.42 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-4gpr-p634-922x is resolved across your whole dependency graph.
Workarounds
Escape or sanitise the affected output on the server side rather than relying on client-side filtering, and add a Content-Security-Policy that blocks inline script execution so injected markup cannot run even if it reaches the page.
Frequently Asked Questions
Is GHSA-4gpr-p634-922x in your dependencies?
Find it across Packagist, including transitive dependencies.