GHSA-fffr-7x4x-f98q is a medium-severity (CVSS 5.9) CWE-770 vulnerability in typo3/cms-core. A fix is available for typo3/cms-core — see the affected versions and patch details below.
TYPO3 CMS vulnerable to Denial of Service in Page Error Handling
Exploitation Status
No confirmed exploitation observed yet
- CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.
Exploitation and automatability from CISA’s SSVC triage for GHSA-fffr-7x4x-f98q.
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.
How urgent is this, really
GHSA-fffr-7x4x-f98q plotted by exploitation likelihood (EPSS) against impact (CVSS). The shaded corner — EPSS 50%+ and CVSS 7.0+ — is where this CVE doesn't sit, though severity or exploitability alone can still warrant action.
Where this sits among everything scored
Of 379,145 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Real counts from FIRST.org, not a sample — log-scaled since the landscape is heavily right-skewed.
Real-World Exposure
typo3/cms-core🐘typo3/cmsReal-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
Meta
- CVSS:
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H/E:F/RL:O/RC:C(5.5)
Problem
Requesting invalid or non-existing resources via HTTP triggers the page error handler which again could retrieve content to be shown as an error message from another page. This leads to a scenario in which the application is calling itself recursively - amplifying the impact of the initial attack until the limits of the web server are exceeded.
This vulnerability is the same as described in TYPO3-CORE-SA-2021-005 (CVE-2021-21359). A regression, introduced during TYPO3 v11 development, led to this situation.
Solution
Update to TYPO3 version 11.5.16 that fixes the problem described above.
Credits
Thanks to Rik Willems who reported this issue and to TYPO3 core & security team member Oliver Hader who fixed the issue.
References
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐘Packagist | typo3/cms-core | ≥ 11.4.0&&< 11.5.16 | 11.5.16composer require typo3/cms-core:^11.5.16 |
| 🐘Packagist | typo3/cms | ≥ 11.4.0&&< 11.5.16 | 11.5.16composer require typo3/cms:^11.5.16 |
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 11.5.16 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-fffr-7x4x-f98q 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-fffr-7x4x-f98q can be triaged on real exposure rather than presence alone.
Tailored to GHSA-fffr-7x4x-f98q. 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-fffr-7x4x-f98q in your dependencies?
O3 Security finds GHSA-fffr-7x4x-f98q across Packagist dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.