react-doctor/webhook-signature-risk

An inbound webhook handler that acts on the request body without verifying the provider's signature will process forged requests from anyone.

Validation prompt

Confirm the detector match and collect the required evidence before deciding whether an edit is warranted.

Fires on a production file identified as an INBOUND webhook handler (its path, or its content with comments/strings stripped, mentions webhook) that exposes an entrypoint: export [async] function POST, export const POST|handler|webhook, webhookHandler, or webhookRoute: and reads the request (req/request), yet shows NO signature-verification evidence anywhere in the file. Evidence that suppresses it: verifySignature/verify*signature/verify*(Webhook|Auth), Stripe constructEvent/stripe.webhooks, createHmac + timingSafeEqual, svix, webhookSecret, or reading a *signature* header. Outbound senders are excluded (process.env.*WEBHOOK_URL, send/post/dispatch/publish/notify*Webhook, and bare webhookUrl mentions are stripped before judging).

Suppress when: verification done in shared middleware or a wrapper in another module (this file has no textual evidence), or a re-export like export const POST = stripeWebhookHandler; whose body lives elsewhere.

Evidence boundary

The diagnostic proves only that the detector’s modeled source pattern matched. It does not prove runtime impact, product intent, rendered failure, or that one remediation is correct.

Establish the environment, repository policy, exceptions, and required rendered or runtime evidence before deciding the occurrence.

Record one outcome:

• Confirmed failure: The required evidence establishes the violation.
• Rejected: A documented exception or false-positive predicate applies.
• Needs evidence: Named evidence can still be collected.
• Unavailable: Required evidence cannot be collected in this run.
• Waived with evidence: An authorized, scoped exception applies to an established failure.
• Observation: The review records an optional tradeoff without claiming a defect.

A waiver records its scope, authority, evidence, and review condition. It is not a pass or false positive.

Default severity is registry metadata. Use the occurrence’s JSON severity after repository configuration when ordering real findings.

Fix prompt

Apply this candidate correction only after the required evidence confirms the risk.

Verify the provider's signature before parsing or acting on the body: use the SDK helper (Stripe webhooks.constructEvent, svix for Clerk) or compute an HMAC over the raw request body with the shared secret and compare with crypto.timingSafeEqual. Use the raw body, not parsed JSON, for the comparison, and reject with 400/401 on mismatch. Keep the webhook secret in server-only env, and if verification lives in shared middleware, confirm it runs for this route.

Repository-wide copy prompt

Use this repository-wide prompt only after validating each occurrence. For one occurrence, use the guidance above.