GHSA-GJ48-438W-JH9V Bleach clean() / Cleaner() fails to sanitize dangerous URI schemes in allowed formaction attributes

Summary Bleach clean / Cleaner fails to sanitize dangerous URI schemes in allowed formaction attributes. Bleach applies URI protocol sanitization only to attributes listed in attrvalisuri. While URI-bearing attributes such as action, href, src, and poster are included in that set, formaction is...