Executive brief
TypeBot is a chatbot builder tool that integrates with Google Sheets for data management. Prior to version 3.17.0, an authenticated user could manipulate OAuth parameters to create Google Sheets credentials in other workspaces and attach them to chatbots they do not own, potentially gaining unauthorized access to sensitive data or modifying chatbot behavior across the platform.
Technical details
The vulnerability is a privilege escalation and authorization bypass in the Google Sheets OAuth callback handler. The endpoint decodes a base64-encoded JSON `state` parameter containing `workspaceId`, `typebotId`, `blockId`, and `redirectUrl` without cryptographic signature verification or integrity protection. Although the callback route is authenticated, it fails to validate that the authenticated user has write access to the target workspace or Typebot before creating credentials or updating blocks. An authenticated attacker who obtains a valid Google OAuth `code` can craft a malicious `state` parameter to create Google Sheets credentials in arbitrary workspaces and, with known target IDs, attach those credentials to blocks in other Typebots. Version 3.17.0 resolves this by implementing signed OAuth state payloads with expiry, user binding, HttpOnly nonce cookies, and enforced authorization checks before credential creation and callback side effects.
Affected products
- TypeBot TypeBot prior to 3.17.0
Timeline
- 2026-08-11: disclosed
- 2026-05-21: patched: Fix merged in version 3.17.0