CVE-2026-48076 open-reception CVE debrief

Who should care

Defenders responsible for OpenReception's appointment booking software, specifically those who manage or use the software for booking appointments, should be aware of this vulnerability and take steps to prevent unauthorized appointment bookings.

Why it matters

CVE-2026-48076 allows an attacker to book an appointment in a private channel without authorization, making private channels fully reachable to anonymous attackers. Defenders should prioritize verifying the affected versions of the appointment booking software and applying patches or mitigations to prevent unauthorized appointment bookings.

• An attacker can book an appointment in a private channel without authorization
• Private channels can be fully reachable to anonymous attackers
• Defenders need to verify the affected versions of the appointment booking software and apply patches or mitigations
• Defenders should monitor for suspicious appointment booking activity

Technical summary

The vulnerability exists in the new-client booking flow of OpenReception's appointment booking software, specifically in versions 1.0.1 and prior. The `createNewClientWithAppointment` function does not check if a channel is public before booking an appointment, allowing an attacker to book an appointment in a private channel by providing a private channel ID obtained through another vulnerability. This issue arises because the `bootstrap-challenge` request schema does not accept a `channelId`, and the issued token's payload contains no channel information. As a result, an attacker can complete the bootstrap flow, receive a valid booking access token, and then submit the `create-new-client` payload with a `chann

Defensive priority

Defenders should prioritize verifying the affected versions of the appointment booking software and applying patches or mitigations to prevent unauthorized appointment bookings.

Recommended defensive actions

• Verify the affected versions of the appointment booking software
• Apply patches or mitigations to prevent unauthorized appointment bookings
• Monitor for suspicious appointment booking activity
• Restrict access to private channels
• Review compensating controls for exposed systems while remediation is scheduled and verified
• Check relevant monitoring, detection, and logs for exposed assets that need extra review
• Track exceptions, retest remediated assets, and close the item only after evidence is documented

Evidence notes

The vulnerability is caused by a missing check for the `channel.isPublic` field in the `createNewClientWithAppointment` function. This allows an attacker to book an appointment in a private channel by providing a private channel ID obtained through another vulnerability.

Sources and references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.