Skipping Webhook Signature Checks Is a Real Security Hole

A webhook endpoint that processes any incoming POST request — without checking where it actually came from — will happily act on a request from anyone who discovers the URL, not just your real integration partner (Stripe, WhatsApp, etc.).

The fix:

most providers sign their webhook payloads with a secret you can verify server-side (a signature header checked against your webhook secret). Verify that signature before processing anything, and reject requests that don't match.