SEV-1: blocks launch
Your Stripe webhook accepts anything
What goes wrong
Someone posts a fake "payment succeeded" event to your endpoint and gets your paid plan for free.
How to fix it
Verify every event with stripe.webhooks.constructEvent, using the raw request body and your webhook signing secret, before you act on it.
Check your app
npx sigshipRun it in your project. It reports this check as stripe-webhook-unverified, along with 16 others. Nothing leaves your machine.