CVE-2026-55089 Etherpad: JWT `admin` claim presence-only check lets non-admin OAuth users invoke every Etherpad HTTP API endpoint

Etherpad is a real-time collaborative editor. From 2.1.0 until 3.1.0, Etherpad's src/node/handler/APIHandler.ts authorizes requests to /api/2/ in the authorizationcode OAuth path by using requiredClaims with the admin claim. This check requires only that the claim exists, while...