The 5 Most Common Messaging‑SDK Vulnerabilities (and How to Fix Them)

Real‑world example shows how a shared bearer token leaked multi‑tenant chat data. Explains why messaging SDKs attract attackers, then deep‑dives into the Top 5 vulnerabilities with fixes. Adds a hands‑on “Security‑Testing in Practice” appendix: pick an open‑source fuzzer or roll a 10‑minute Postman/Python harness.

1.  The Chatbot That Leaked Client Messages

A SaaS integrator stitched together several chat platforms behind a single bearer token to “keep things simple.” One afternoon, a customer‑support bot sent invoices meant for Tenant A to the phone numbers of Tenant B.
Root cause → the shared token had enough scope to act on any tenant; when the job slipped the wrong account_id, the API happily complied.

Why it matters: Multi‑tenant messaging amplifies every auth mistake—just ask Microsoft, where the 2023 Storm‑0558 breach showed how a single signing key enabled ...