CVE-2026-66370 html_sanitize_ex HTML5 scrubber keeps attacker-supplied form-association attributes, allowing form hijacking

URL Redirection to Untrusted Site 'Open Redirect' vulnerability in the HTML5 scrubber in rrrene htmlsanitizeex allows an unauthenticated remote attacker to retarget a form already on the rendering page and receive whatever the victim submits, including credentials, via the form and formaction...