GHSA-x428-565f-8xj2 is a high-severity (CVSS 8.8) remote code execution vulnerability in typo3/cms-core. A fix is available for typo3/cms-core — see the affected versions and patch details below.
TYPO3 Arbitrary Code Execution and Cross-Site Scripting in Backend API
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
Backend API configuration using Page TSconfig is vulnerable to arbitrary code execution and cross-site scripting. TSconfig fields of page properties in backend forms can be used to inject malicious sequences. Field tsconfig_includes is vulnerable to directory traversal leading to same scenarios as having direct access to TSconfig settings.
A valid backend user account having access to modify values for fields pages.TSconfig and pages.tsconfig_includes is needed in order to exploit this vulnerability.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐘Packagist | typo3/cms-core | ≥ 8.0.0&&< 8.7.27 | 8.7.27composer require typo3/cms-core:^8.7.27 |
| 🐘Packagist | typo3/cms-core | ≥ 9.0.0&&< 9.5.8 | 9.5.8composer require typo3/cms-core:^9.5.8 |
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 8.7.27 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-x428-565f-8xj2 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-x428-565f-8xj2 can be triaged on real exposure rather than presence alone.
Tailored to GHSA-x428-565f-8xj2. 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-x428-565f-8xj2 in your dependencies?
O3 Security finds GHSA-x428-565f-8xj2 across Packagist dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.