CVE-2026-63506: Tina: [Broken Access Control] letting any TinaCloud user authorize against any self-hosted site

Severity: high (CVSS 8.8 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.5% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-09-16 · updated 2026-09-30
Weakness: CWE-639

Description

Tina is a headless content management system. Prior to @tinacms/auth 1.1.4 and next-tinacms-azure 15.0.1, isAuthorized accepts a request-controlled clientID and asks isUserAuthorized to validate the bearer token against that selected TinaCloud app instead of the self-hosted site's configured app. An attacker with any TinaCloud account can submit the attacker's own app ID and valid token to a victim endpoint, causing TinaCloudBackendAuthProvider or an affected media authorized callback to accept the attacker's verified status across the tenant boundary. The vulnerable logic is present in packages/@tinacms/auth/src/index.ts and packages/next-tinacms-azure/src/auth.ts. Successful exploitation permits media listing, reading, upload, or deletion and, when TinaCloudBackendAuthProvider is used, GraphQL read, create, update, and delete operations on the victim's content without a victim account or victim interaction. This vulnerability is fixed in @tinacms/auth 1.1.4 and next-tinacms-azure 15.0.1.

Affected products

@tinacms auth: before 1.1.4
tinacms next-tinacms-azure: before 15.0.1
tinacms: before 1.1.4

References

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