CVE-2026-48088: OpenReception vulnerable to unauthenticated staff crypto poisoning that breaks E2E recipient directory

OpenReception's appointment booking software provides an end-to-end encrypted appointment booking platform. Prior to version 1.0.4, the route POST /api/tenants/{tenantId}/staff/{staffId}/crypto accepts and stores attacker-controlled ML-KEM-768 public keys against any tenant on the platform without authentication. The handler logs an "Unauthorized crypto key storage attempt" warning when neither a session nor a registration cookie is present, then proceeds to insert the row regardless. The platform's E2E claim that "even administrators cannot view sensitive information" is broken: any unauthenticated network attacker can register themselves as an additional encryption recipient for any tenant's future patient appointments. A second variant of the bug suppresses the unauthorized-warning log entry. The Zod schema makes the email field optional. When the request body omits email and the request carries no registration cookie, the comparison registrationEmail === email becomes undefined === undefined, which evaluates to true. The handler treats the request as a legitimate registration flow, skips the warning entirely, and stores the row. Successful storage is still recorded as an [info] log line, but the security-relevant warning that operators are most likely to monitor or alert on is gone. The staffcrypto table has no unique constraint on userid, so an arbitrary number of attacker rows can coexist for the same staff identifier and all return as isactive=true. The supplied staffId does not need to match any existing user or pending invite. Schema validation on passkeyId, publicKey, and privateKeyShare is also weak: the literal string <placeholder-base64> was accepted, indicating no length, format, or cryptographic-validity check beyond field presence. This weakness is independent of the auth bypass but compounds it: a poisoned directory can also be filled with malformed entries that break legitimate booking flows. The injected key is consumed by the public booking flow. After completing the unauthenticated bootstrap-challenge and bootstrap-verify ceremony as a "patient", the resulting bookingAccessToken is accepted by GET /api/tenants/{id}/appointments/staff-public-keys, which returns the attacker-controlled keys alongside any legitimate ones. A new appointment encrypts its tunnel key with ML-KEM to all listed recipients, so the attacker becomes a co-recipient of the encryption and can decapsulate the tunnel key with the matching secret. From there, all appointment payloads for that booking are decryptable. Version 1.0.4 patches the issue.