[SECURITY] Mitigate XSS in CDATA and HTML raw text elements #106
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Due to a parsing issue in upstream package `masterminds/html5`, malicious markup used in a sequence with special HTML CDATA sections cannot be filtered and sanitized. This change mitigates the parsing problem by converting all CDATA section contents to DOM text nodes like show below: - from `<![CDATA[<any><span data-value="value"></any>*/]]>` + to `<any><span data-value="value"></any>*/` In case an individual builder us used, which does not inherit behavior declarations from `TYPO3\HtmlSanitizer\Builder\CommonBuilder`, those implementations need to be adjusted manually.
Upstream package `masterminds/html5` provides HTML raw text elements (`script`, `style`, `noframes`, `noembed` and (void element) `iframe`) as `DOMText` nodes. Since those text nodes have not been processed by `typo3/html-sanitizer`, sanitization was not applied to mentioned HTML tag names. None of them 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. In case any of those tags shall be processed as raw text (for instance this would be reasonable for `script type="ld+json"`), the new `Behavior\Tag::ALLOW_INSECURE_RAW_TEXT` flag needs to be used explicitly.
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Security-References: CVE-2022-23499