Namespace attributes are not encoded correctly during HTML serialization. This allows bypassing the cross-site scripting prevention mechanism of `typo3/html-sanitizer` before version 2.3.2. Credits to Doyensec in collaboration with Claude and Anthropic Research for reporting this vulnerability.
Update typo3/html-sanitizer to 2.3.2 if you use the affected versions. Test the change in a non-production environment first.
Local check
hol-guard supply-chain scanTYPO3 HTML Sanitizer allows Cross-site Scripting affects typo3/html-sanitizer (composer). Severity is medium. Namespace attributes are not encoded correctly during HTML serialization. This allows bypassing the cross-site scripting prevention mechanism of `typo3/html-sanitizer` before version 2.3.2. Credits to Doyensec in collaboration with Claude and Anthropic Research for reporting this vulnerability.
AI coding agents often install or upgrade packages automatically in composer. A medium vulnerability in a dependency can be pulled into a project through a normal install or update without a human reviewing the change, expanding the blast radius from a single package to every agent workspace that depends on it.
| Package | Affected range | Fixed version |
|---|---|---|
| typo3/html-sanitizercomposer | <2.3.2 | 2.3.2 |
Fixed versions are reported by the source feed; confirm compatibility before updating.
Namespace attributes are not encoded correctly during HTML serialization. This allows bypassing the cross-site scripting prevention mechanism of `typo3/html-sanitizer` before version 2.3.2. Credits to Doyensec in collaboration with Claude and Anthropic Research for reporting this vulnerability.
Update typo3/html-sanitizer to 2.3.2 if you use the affected versions. Test the change in a non-production environment first.
Local check
hol-guard supply-chain scanTYPO3 HTML Sanitizer allows Cross-site Scripting affects typo3/html-sanitizer (composer). Severity is medium. Namespace attributes are not encoded correctly during HTML serialization. This allows bypassing the cross-site scripting prevention mechanism of `typo3/html-sanitizer` before version 2.3.2. Credits to Doyensec in collaboration with Claude and Anthropic Research for reporting this vulnerability.
AI coding agents often install or upgrade packages automatically in composer. A medium vulnerability in a dependency can be pulled into a project through a normal install or update without a human reviewing the change, expanding the blast radius from a single package to every agent workspace that depends on it.
| Package | Affected range | Fixed version |
|---|---|---|
| typo3/html-sanitizercomposer | <2.3.2 | 2.3.2 |
Fixed versions are reported by the source feed; confirm compatibility before updating.
Reported by GitHub Security Advisories (ghsa).
HOL Guard can help your team review package activity against supported protection paths.
Explore HOL GuardReported by GitHub Security Advisories (ghsa).
HOL Guard can help your team review package activity against supported protection paths.
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