Crabbox < 0.9.0 Authentication Bypass via Admin Claim Injection

Crabbox before 0.9.0 contains an authentication bypass vulnerability in the coordinator user-token verification path where the verifyUserToken() function fails to reject payloads containing an admin claim, allowing attackers to escalate privileges. An attacker with access to the shared non-admin token can craft a user-token payload with admin: true, sign it using HMAC-SHA256, and present it to admin-only coordinator routes to gain full coordinator admin access including lease visibility, pool state management, and forced release operations.