XSS in Typo3 Html-Sanitizer

CVE-2022-36020

The typo3/html-sanitizer package is an HTML sanitizer, written in PHP, aiming to provide XSS-safe markup based on explicitly allowed tags, attributes and values. Due to a parsing issue in the upstream package `masterminds/html5`, malicious markup used in a sequence with special HTML comments cannot be filtered and sanitized. This allows for a bypass of the cross-site scripting mechanism of `typo3/html-sanitizer`. This issue has been addressed in versions 1.0.7 and 2.0.16 of the `typo3/html-sanitizer` package. Users are advised to upgrade. There are no known workarounds for this issue.

Vulnerability class: XSS (Cross-Site Scripting)

EPSS: 0.007 (47.8th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 6.1 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N.

Affected products

Weakness classification (CWE)

Public proof-of-concept exploits

References

Frequently asked questions

What is CVE-2022-36020?
CVE-2022-36020 is a medium-severity vulnerability in Typo3 Html-Sanitizer, classified under Cross-site Scripting. CVSS score: 6.1/10. Published 2022-09-13.
How severe is CVE-2022-36020?
Medium severity. CVSS v3 base score is 6.1 out of 10.
Is CVE-2022-36020 known to be exploited?
1 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.