The bug resides in the WhatsApp test‑webhook handler of TypeBot version 3.16.1. An attacker who is authenticated with read access can combine a legitimate typebot identifier, block identifier, and a foreign preview phone number tied to another preview session. The handler first authorizes the parent bot, then resolves the preview session solely by the global wa‑preview‑{phone} key, allowing the attacker to inject arbitrary webhook JSON into another workplace's preview session and advance an unpublished flow without ownership of that bot. This reflects a CWE‑639 type weakness in which user‑controlled data leads to unauthorized access.

The vulnerability affects the TypeBot.io chatbot builder provided by baptisteArno. Versions prior to 3.17.0, specifically 3.16.1, are vulnerable when the WhatsApp preview feature is enabled. No patches were available before 3.17.0, and the issue is tied to bots that expose read access and use the global wa‑preview‑{phone} session identifier.

The CVSS base score of 7.1 indicates a high impact, while the EPSS score of less than 1 % suggests a very low exploitation probability at present. The vulnerability is not listed in the CISA KEV catalog. Exploitation requires an authenticated user with read access and knowledge of a valid preview phone number; once those conditions are met, the attacker can alter other bots’ unpublished flows.