CVE-2026-31816 PoC — Budibase Universal Auth Bypass via Webhook Query Param Injection

Title:Budibase Universal Auth Bypass via Webhook Query Param Injection (CVE-2026-31816)
Description:Budibase is a low code platform for creating internal tools, workflows, and admin panels. In 3.31.4 and earlier, the Budibase server's authorized() middleware that protects every server-side API endpoint can be completely bypassed by appending a webhook path pattern to the query string of any request. The isWebhookEndpoint() function uses an unanchored regex that tests against ctx.request.url, which in Koa includes the full URL with query parameters. When the regex matches, the authorized() middleware immediately calls return next(), skipping all authentication, authorization, role checks, and CSRF protection. This means a completely unauthenticated, remote attacker can access any server-side API endpoint by simply appending ?/webhooks/trigger (or any webhook pattern variant) to the URL.

Budibase <= 3.31.4 contains an authentication bypass caused by unanchored regex in authorized() middleware matching webhook path patterns in query strings, letting unauthenticated remote attackers access any server-side API endpoint, exploit requires crafted request with webhook pattern in URL.

 id: CVE-2026-31816

info:
  name: Budibase - Authentication Bypass
  author: theamanrawat
  severity

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