BIT-DISCOURSE-2026-72720 Discourse: HTML injection in PrettyText.format_for_email from cooked-attribute reparsing

Discourse is an open-source discussion platform. Prior to 2026.1.7, 2026.6.2, 2026.7.1, and 2026.8.0, Discourse has HTML injection in PrettyText.formatforemail because cooked attribute values are reparsed as markup. Crafted Vimeo iframe sources, secure-upload URLs or dimensions, and hashtag...