CVE-2026-55660 TinaCMS: Cross-origin postMessage handlers and rich-text URL-sanitization bypass enable stored XSS and session takeover

Tina is a headless content management system. In versions prior to @tinacms/app 2.5.6 and tinacms 3.9.3, cross-origin postMessage handlers and a rich-text URL-sanitization bypass enable stored XSS and session takeover. The library registers window message listeners — the useTina overlay handler,...

CVE-2026-55660

CVE-2026-55660 : TinaCMS and Tinacms app prior to versions 2.5.6 / 3.9.3 allow cross-origin postMessage abuse due to window message listeners that do not validate event.origin/source and post to non-specific origins, combined with insufficient URL sanitization in rich-text content. This enables s...

CVE-2026-55660

Tina is a headless content management system. In versions prior to @tinacms/app 2.5.6 and tinacms 3.9.3, cross-origin postMessage handlers and a rich-text URL-sanitization bypass enable stored XSS and session takeover. The library registers window message listeners — the useTina overlay handler,...