---
id: CVE-2026-48087
title: >-
  OpenReception's appointment booking software provides an end-to-end encrypted
  appointment booking platform
summary: >-
  OpenReception's appointment booking software provides an end-to-end encrypted
  appointment booking platform. Prior to version 1.0.2, the registration handler
  at `POST /api/auth/register/{userId}` validates the relationship between the
  Web…
severity: critical
cvss: 9.8
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H'
cwe:
  - CWE-287
published: '2026-08-06'
updated: '2026-09-08'
sourceUpdated: '2026-09-08T20:51:43.490'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-48087'
references:
  - url: >-
      https://github.com/open-reception/appointment-booking-software/commit/5f61a2116d68378366edd712c343a9de7b205a74
    label: security-advisories@github.com
  - url: >-
      https://github.com/open-reception/appointment-booking-software/security/advisories/GHSA-j9rw-x2wv-h5rj
    label: security-advisories@github.com
tags:
  - nvd
epss: 0.00574
epssPercentile: 0.4502
ingestedAt: '2026-09-08T21:11:12.270Z'
---

## Overview

OpenReception's appointment booking software provides an end-to-end encrypted appointment booking platform. Prior to version 1.0.2, the registration handler at `POST /api/auth/register/{userId}` validates the relationship between the WebAuthn challenge and the registration cookie's email but never validates that the `userId` in the URL belongs to that email. An unauthenticated attacker requests a challenge for their own email, generates a registration response with their own authenticator, and submits it against any victim user's URL. The challenge-vs-cookie email match passes, the WebAuthn ceremony validates, and `addPasskey` writes the attacker's credential into the victim's `user_passkey` rows. The next victim-email login accepts a passkey assertion from the attacker's authenticator and issues a session as the victim. User IDs are not strictly secret on this platform, but the exact set of exposure surfaces should be assessed by the maintainers. Staff-list endpoints return user IDs to authenticated tenant members per the route signature; live verification of all exposure surfaces (whether user IDs leak through any unauthenticated route, through invite-confirmation URLs, or through other administrative views) is part of the pending live PoC. Where the attacker knows the victim's email and userId, the analysis below becomes account takeover. Version 1.0.2 fixes the issue.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.