TinaCMS admin preview iframe loads an attacker-controlled origin from the URL fragment

Summary

Tina is a headless content management system. Prior to tinacms 3.14.0 and @tinacms/app 2.5.14, the /~/* admin preview route in packages/tinacms/src/admin/index.tsx can turn an attacker-controlled hash-router splat into an off-origin iframe URL through packages/@tinacms/app/src/preview.tsx, while packages/@tinacms/app/src/lib/preview-origin.ts derives expectedOrigin from that same URL for the GraphQL message channel in packages/@tinacms/app/src/lib/graphql-reducer.ts. An unauthenticated attacker can send a crafted link to a signed-in editor, cause the admin to frame an attacker origin, and have that frame treated as the trusted preview. The attacker-controlled frame can submit GraphQL reads or mutations that the admin executes with the editor credentials, exposing or modifying protected content. This issue is fixed in tinacms 3.14.0 and @tinacms/app 2.5.14.

Timeline

1. Oct 9, 2026, 8:43 PM UTCCVE published
2. Oct 13, 2026, 11:22 AM UTCCISA SSVC assessment

   Exploitation: poc · Automatable: no · Technical impact: total

3. Oct 13, 2026, 11:24 AM UTCRecord last updated

Affected versions

• tinacms tinacms

  fixed in 3.14.0

• @tinacms app

  fixed in 2.5.14

• tinacmsnpm

  fixed in 3.14.0

• @tinacms/appnpm

  fixed in 2.5.14

References 5