Cross-Site Scripting Protection bypass in HTML Sanitizer
Description
HTML sanitizer is written in PHP, aiming to provide XSS-safe markup based on explicitly allowed tags, attributes and values. In versions prior to 1.5.0 or 2.1.1, malicious markup used in a sequence with special HTML CDATA sections cannot be filtered and sanitized due to a parsing issue in the upstream package masterminds/html5. This allows bypassing the cross-site scripting mechanism of typo3/html-sanitizer. 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. This issue has been fixed in versions 1.5.0 and 2.1.1.
AI Insight
LLM-synthesized narrative grounded in this CVE's description and references.
The typo3/html-sanitizer PHP library before versions 1.5.0 and 2.1.1 fails to sanitize HTML CDATA sections due to a parsing issue, allowing potential XSS bypass in custom configurations.
Vulnerability
Description CVE-2022-23499 is a cross-site scripting (XSS) bypass vulnerability in the typo3/html-sanitizer PHP library, which sanitizes HTML to prevent XSS. The issue stems from a parsing flaw in the upstream package masterminds/html5, where HTML CDATA sections are not correctly processed. Raw text elements such as script, style, noframes, noembed, and iframe are treated as DOMText nodes and consequently not sanitized. [1]
Exploitation
Conditions To exploit this vulnerability, an attacker must supply malicious markup that includes CDATA sections containing one of the vulnerable raw text elements. However, the default builder configuration of typo3/html-sanitizer does not include these tags in its allowlist. Therefore, only custom behaviors that explicitly permit those tags are susceptible to XSS. [1]
Impact
If exploited, an attacker can inject arbitrary JavaScript into a web application that uses a vulnerable custom configuration, leading to XSS attacks. This could result in session theft, website defacement, or other malicious actions. [1]
Mitigation
The issue has been fixed in versions 1.5.0 and 2.1.1 of typo3/html-sanitizer. Users are strongly advised to update to the latest patched release. Additionally, ensuring that only necessary tags are allowed in custom configurations reduces exposure. [1][3][4]
AI Insight generated on May 20, 2026. Synthesized from this CVE's description and the cited reference URLs; citations are validated against the source bundle.
Affected packages
Versions sourced from the GitHub Security Advisory.
| Package | Affected versions | Patched versions |
|---|---|---|
typo3/html-sanitizerPackagist | >= 1.0.0, < 1.5.0 | 1.5.0 |
typo3/html-sanitizerPackagist | >= 2.0.0, < 2.1.1 | 2.1.1 |
typo3/cmsPackagist | >= 10.0.0, < 10.4.33 | 10.4.33 |
typo3/cmsPackagist | >= 11.0.0, < 11.5.20 | 11.5.20 |
typo3/cmsPackagist | >= 12.0.0, < 12.1.1 | 12.1.1 |
Affected products
3- ghsa-coords2 versions
>= 10.0.0, < 10.4.33+ 1 more
- (no CPE)range: >= 10.0.0, < 10.4.33
- (no CPE)range: >= 1.0.0, < 1.5.0
- TYPO3/html-sanitizerv5Range: >= 1.0.0, < 1.5.0
Patches
0No patches discovered yet.
Vulnerability mechanics
AI mechanics synthesis has not run for this CVE yet.
References
9- github.com/advisories/GHSA-hvwx-qh2h-xcfjghsaADVISORY
- nvd.nist.gov/vuln/detail/CVE-2022-23499ghsaADVISORY
- github.com/FriendsOfPHP/security-advisories/blob/master/typo3/cms/CVE-2022-23499.yamlghsaWEB
- github.com/TYPO3/html-sanitizer/pull/105ghsaWEB
- github.com/TYPO3/html-sanitizer/pull/106ghsaWEB
- github.com/TYPO3/html-sanitizer/releases/tag/v1.5.0ghsaWEB
- github.com/TYPO3/html-sanitizer/releases/tag/v2.1.1ghsaWEB
- github.com/TYPO3/html-sanitizer/security/advisories/GHSA-hvwx-qh2h-xcfjghsax_refsource_CONFIRMWEB
- typo3.org/security/advisory/typo3-core-sa-2022-017ghsaWEB
News mentions
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