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

Why it is Amber

• CVSS 9.3 critical
• Remotely exploitable without logging in
• On your watchlist: npm

Affected packages

References

• https://github.com/advisories/GHSA-x34j-47hf-4xg7
• https://github.com/tinacms/tinacms/security/advisories/GHSA-x34j-47hf-4xg7
• https://github.com/tinacms/tinacms/pull/7522
• https://github.com/tinacms/tinacms/commit/b57dbf4b56201aef15cd92caa49fd12ab96bbecf
• https://github.com/tinacms/tinacms/releases/tag/@tinacms/app@2.5.14
• https://github.com/tinacms/tinacms/releases/tag/tinacms@3.14.0
• https://github.com/advisories/GHSA-x34j-47hf-4xg7

Original description

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.