GHSA-h4mx-xv96-2jgm is a medium-severity (CVSS 5.4) Cross-site Scripting (XSS) vulnerability in typo3/cms-core. A fix is available for typo3/cms-core — see the affected versions and patch details below.
Cross-Site Scripting in TYPO3's Frontend Login Mailer
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-h4mx-xv96-2jgm.
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-h4mx-xv96-2jgm 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/cms-core🐘typo3/cms-core🐘typo3/cms🐘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:L/PR:L/UI:R/S:C/C:L/I:L/A:N/E:F/RL:O/RC:C(4.9)
Problem
User submitted content was used without being properly encoded in HTML emails sent to users. The actually affected components were mail clients used to view those messages.
Solution
Update to TYPO3 versions 9.5.35 ELTS, 10.4.29, 11.5.11 that fix the problem described above.
Credits
Thanks to Christian Seifert who reported this issue and to TYPO3 framework merger Andreas Fernandez who fixed the issue.
References
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐘Packagist | typo3/cms-core | ≥ 9.0.0&&< 9.5.35 | 9.5.35composer require typo3/cms-core:^9.5.35 |
| 🐘Packagist | typo3/cms-core | ≥ 10.0.0&&< 10.4.29 | 10.4.29composer require typo3/cms-core:^10.4.29 |
| 🐘Packagist | typo3/cms-core | ≥ 11.0.0&&< 11.5.11 | 11.5.11composer require typo3/cms-core:^11.5.11 |
| 🐘Packagist | typo3/cms | ≥ 10.0.0&&< 10.4.29 | 10.4.29composer require typo3/cms:^10.4.29 |
| 🐘Packagist | typo3/cms | ≥ 11.0.0&&< 11.5.11 | 11.5.11composer require typo3/cms:^11.5.11 |
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 9.5.35 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-h4mx-xv96-2jgm 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-h4mx-xv96-2jgm can be triaged on real exposure rather than presence alone.
Tailored to GHSA-h4mx-xv96-2jgm. 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-h4mx-xv96-2jgm in your dependencies?
O3 Security finds GHSA-h4mx-xv96-2jgm across Packagist dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.