CVE-2026-48071 OpenReception's client PIN challenge throttle is keyed by emailHash only, allowing cross-tenant lockout
Attackers can lock out patients across different tenants by exploiting a shared throttle key, causing sustained denial of service.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-48071?
CVE-2026-48071 is a medium-severity denial of service vulnerability in open-reception appointment-booking-software, published on 6 Aug 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
OpenReception's appointment booking software provides an end-to-end encrypted appointment booking platform. Prior to version 1.0.4, the PIN-type challenge throttle uses `emailHash` as the only key. The throttle rows live in the central `challenge_throttle` table, which is shared across all tenants. Every tenant's `/api/tenants/{id}/appointments/verify-challenge` endpoint increments the same row when a PIN response fails, and every tenant's `/api/tenants/{id}/appointments/challenge` endpoint reads the same row when deciding whether to issue a new challenge. When the same `emailHash` exists in multiple tenants on the same OpenReception instance (the same patient holding tunnels in two different clinics that share the platform), an attacker who knows the patient's email can lock out that patient on tenant B by issuing failed challenge responses against tenant A. The attacker needs no relationship to tenant B; the lockout propagates through the shared throttle row. The lockout escalates with repeated failures. The first lockout triggers at 4 failed attempts and lasts approximately 60 seconds. Subsequent failures escalate the lockout duration to 5 minutes, 30 minutes, and 60 minutes per the throttle service's escalation logic. Repeated bursts produce sustained denial of service against the targeted email. Version 1.0.4 patches the issue.
Weakness: CWE-307
Which versions are affected by CVE-2026-48071?
How do I fix CVE-2026-48071?
No fix has been published for CVE-2026-48071 yet. Limit exposure of the affected software until one is available.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2026-48071 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-48071 exists.
Sources
Also known as GHSA-f778-wf9x-3qf9.