OpenReception's appointment booking software provides an end-to-end encrypted appointment booking…

Why it is Amber

• CVSS 8.3 high
• Remotely exploitable without logging in

References

• https://github.com/open-reception/appointment-booking-software/commit/df5432776a1a5b47c3a64d64e9d05dbe2b7a7819
• https://github.com/open-reception/appointment-booking-software/releases/tag/v2.0.0
• https://github.com/open-reception/appointment-booking-software/security/advisories/GHSA-w5g9-g2p4-2g4m

Original description

OpenReception's appointment booking software provides an end-to-end encrypted appointment booking platform. Prior to version 2.0.0, the account-confirmation link in emails is built from the request Host header, with no allowlist. The unauthenticated POST /api/auth/resend-confirmation rotates a pending invitee's confirmation token and emails a link whose host comes from the request. An attacker who sends one resend-confirmation with Host: attacker.example and a pending invitee's email causes that invitee to receive a confirmation email whose only link points to the attacker. If the invitee clicks, the one-time confirmation token reaches the attacker, who then confirms the account on the real tenant domain and registers a passkey they control, taking over the account before the legitimate invitee ever uses it. All released versions through v1.1.0 are affected; no patched version exists yet. Reaching the app with a spoofed Host depends on the front proxy: the stock Caddy catch-all forwards it, while an operator who configures explicit per-tenant proxy blocks is not affected (see Details 4). The invite path builds links from the trusted tenant.domain (invite/+server.ts:204-210); the resend-confirmation path builds them from the request Host. This issue has been patched in version 2.0.0.