GHSA-4459-qrcc-vfcf is a medium-severity (CVSS 6.1) vulnerability in typo3/cms-core. A fix is available for typo3/cms-core — see the affected versions and patch details below.
Real-World Exposure
typo3/cms-core🐘typo3/cms-coreReal-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
Failing to properly encode user input, frontend forms handled by the form framework (system extension “form”) are vulnerable to cross-site scripting.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐘Packagist | typo3/cms-core | ≥ 8.5.0&&< 8.7.23 | 8.7.23composer require typo3/cms-core:^8.7.23 |
| 🐘Packagist | typo3/cms-core | ≥ 9.0.0&&< 9.5.4 | 9.5.4composer require typo3/cms-core:^9.5.4 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for typo3/cms-core, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update typo3/cms-core to 8.7.23 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-4459-qrcc-vfcf 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-4459-qrcc-vfcf in your dependencies?
Find it across Packagist, including transitive dependencies.