GHSA-hvwx-qh2h-xcfj is a medium-severity (CVSS 6.1) Cross-site Scripting (XSS) vulnerability in typo3/html-sanitizer. A fix is available for typo3/html-sanitizer — see the affected versions and patch details below.
TYPO3 HTML Sanitizer vulnerable to Cross-Site Scripting
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-hvwx-qh2h-xcfj 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/html-sanitizer🐘typo3/html-sanitizer🐘typo3/cms🐘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
Problem
Due to a parsing issue in the upstream package masterminds/html5, malicious markup used in a sequence with special HTML CDATA sections cannot be filtered and sanitized. This allows bypassing the cross-site scripting mechanism of typo3/html-sanitizer.
Besides that, the upstream package masterminds/html5 provides HTML raw text elements (script, style, noframes, noembed and iframe) as DOMText nodes, which were not processed and sanitized further. None of the mentioned elements were defined in the default builder configuration, that's why only custom behaviors, using one of those tag names, were vulnerable to cross-site scripting.
Solution
Update to typo3/html-sanitizer versions 1.5.0 or 2.1.1 that fix the problem described.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐘Packagist | typo3/html-sanitizer | ≥ 1.0.0&&< 1.5.0 | 1.5.0composer require typo3/html-sanitizer:^1.5.0 |
| 🐘Packagist | typo3/html-sanitizer | ≥ 2.0.0&&< 2.1.1 | 2.1.1composer require typo3/html-sanitizer:^2.1.1 |
| 🐘Packagist | typo3/cms | ≥ 10.0.0&&< 10.4.33 | 10.4.33composer require typo3/cms:^10.4.33 |
| 🐘Packagist | typo3/cms | ≥ 11.0.0&&< 11.5.20 | 11.5.20composer require typo3/cms:^11.5.20 |
| 🐘Packagist | typo3/cms | ≥ 12.0.0&&< 12.1.1 | 12.1.1composer require typo3/cms:^12.1.1 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for typo3/html-sanitizer, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update typo3/html-sanitizer to 1.5.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-hvwx-qh2h-xcfj 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-hvwx-qh2h-xcfj can be triaged on real exposure rather than presence alone.
Tailored to GHSA-hvwx-qh2h-xcfj. 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-hvwx-qh2h-xcfj in your dependencies?
O3 Security finds GHSA-hvwx-qh2h-xcfj across Packagist dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.