GHSA-HHG7-C65M-H7FF Symfony's HtmlSanitizer UrlAttributeSanitizer Omits action/formaction/poster/cite — `javascript`: URI Survives Sanitization (XSS)

Description symfony/html-sanitizer lets applications sanitise untrusted HTML. UrlAttributeSanitizer is the visitor responsible for validating URL-valued attributes and stripping dangerous schemes from them; it runs on every element regardless of configuration. Whether an attribute is kept is...

PT-2026-44727

Name of the Vulnerable Software and Affected Versions symfony/html-sanitizer versions prior to 6.4 Description The UrlAttributeSanitizer visitor fails to validate the schemes of several URL-valued attributes because they are missing from the getSupportedAttributes list. Specifically, the action...

GHSA-4952-P58Q-6CRX JupyterLab: XSS due to lack of sanitization of the action attribute of an html <form>

Impact Untrusted notebook can execute code on load. This is a remote code execution, but requires user action to open a notebook. Patches Patched in the following versions: 3.1.4, 3.0.17, 2.3.2, 2.2.10, 1.2.21. References OWASP Page on Restricting Form Submissions For more information If you have...

CVE-2026-45753: HtmlSanitizer UrlAttributeSanitizer Omits action/formaction/poster/cite: javascript: URI Survives Sanitization (XSS)

More info at https://symfony.com/cve-2026-45753...