TYPO3 HTML Sanitizer allows Cross-site Scripting
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.
Affected software
Click a technology to see all vulnerabilities affecting it.
| Platform | Package | Vulnerable versions | Fixed in |
|---|---|---|---|
| Composer package | typo3/html-sanitizer | < 2.3.2 | 2.3.2 |
References
- https://github.com/TYPO3/html-sanitizer/security/advisories/GHSA-p5j5-4j3q-8mq8
- https://nvd.nist.gov/vuln/detail/CVE-2026-47345
- https://github.com/TYPO3/html-sanitizer/commit/8b5d0be44ded457ca993ec9ca93d859941c63764
- https://github.com/FriendsOfPHP/security-advisories/blob/master/typo3/html-sanitizer/CVE-2026-47345.yaml
- https://github.com/TYPO3/html-sanitizer
- https://typo3.org/security/advisory/typo3-core-sa-2026-006
- CVSS vector
CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:P/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N- Weakness (CWE)
CWE-79- Platform
- Composer
- Package
typo3/html-sanitizer- Disclosed
- 12.06.2026
- Updated
- 11.10.2026 10:22
Sources and licenses
OSV / GitHub Advisory Database - GHSA-p5j5-4j3q-8mq8 - CC BY 4.0
Vulnerability history: typo3/html-sanitizer
All published vulnerabilities of this package (Composer package), newest first. Shows whether this is a one-off slip or a package that needs watching.
- Total entries
- 6
- First → latest
- 09.2022 06.2026
- Without a fix
- 0
- Exploited in attacks
- 0
Severity breakdown
- Medium 5
- Low 1
Disclosures per year
- 2022: 2
- 2023: 2
- 2024: 0
- 2025: 0
- 2026: 2
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TYPO3 HTML Sanitizer allows Cross-site Scripting this entry
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