TypeBot is a chatbot builder tool. Prior to version 3.17.0, the Google Sheets OAuth callback decodes a base64-encoded JSON state parameter and trusts the embedded workspaceId, typebotId, blockId, and redirectUrl without cryptographic integrity protection or authorization checks. The callback route is authenticated, but it does not verify that the authenticated user has write access to the target workspace or Typebot before creating credentials in the workspace or updating Typebot groups. An authenticated user who can obtain a valid Google OAuth code can alter the state value to create Google Sheets credentials in another workspace and, if target IDs are known, attach those credentials to a block in another Typebot. Version 3.17.0 patches the issue.