TYPO3 HTML Sanitizer allows Cross-Site Scripting
CVE-2026-47345

5.1MEDIUM

Key Information:

Vendor

Typo3

Status
Html Sanitizer
Vendor
CVE Published:
8 June 2026

What is CVE-2026-47345?

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.

Affected Version(s)

HTML Sanitizer 0 < 2.3.2

References

https://typo3.org/security/advisory/typo3-core-sa-2026-006
vendor-advisory
https://github.com/TYPO3/html-sanitizer/commit/8b5d0be44d...
patch

CVSS V4

Score:
5.1
Severity:
MEDIUM
Confidentiality:
None
Integrity:
None
Availability:
None
Attack Vector:
Network
Attack Complexity:
Low
Attack Required:
None
Privileges Required:
Undefined
User Interaction:
Unknown

Timeline

  • Vulnerability published

  • Vulnerability Reserved

Credit

Doyensec in collaboration with Claude and Anthropic Research
Benjamin Franzke
.