appointment-booking-software: Improper Restriction of Excessive Authentication Attempts
CVE-2026-65825 is a high-severity improper restriction of excessive authentication attempts vulnerability in appointment-booking-software from Open-reception, with a CVSS 3.1 base score of 7.5 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. Affected appointment-booking-software versions: <= 2.1.0. The record does not name a fixed version, so check the vendor advisory. There is no confirmed exploitation so far. EPSS estimates a 0.22% chance of exploitation within 30 days, which is low compared with other CVEs.
High severity with no evidence of exploitation so far.
What to do
- Check which version of appointment-booking-software you run against the affected versions below, and install the vendor's latest release.
- Read the advisory on github.com for workarounds and exact fixed builds.
- Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Open-reception | appointment-booking-software | <= 2.1.0 | Not stated |
Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- NetworkCan be exploited remotely over a network, including the internet.
- Attack complexity
- HighSuccess depends on conditions outside the attacker's control.
- Privileges required
- NoneNo account or login is needed.
- User interaction
- NoneNo action by a victim is required.
- Scope
- ChangedThe attack can reach beyond the vulnerable component into other systems.
- Confidentiality
- HighAll data handled by the component can be read.
- Integrity
- LowLimited modification of data is possible.
- Availability
- NoneAvailability is not affected.
Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:L/A:N. Scored by CNA (github.com).
Official description
OpenReception's appointment booking software provides an end-to-end encrypted appointment booking platform. In versions 2.1.0 and prior, a returning client's six-digit booking PIN can be brute-forced online in the victim tenant. A successful guess yields the client's booking access token, granting access to that client's appointment tunnel, which holds their end-to-end-encrypted appointment data, and the ability to act as the client, for example adding or cancelling appointments in the tunnel. The bypass is cross-tenant: state owned by one tenant removes an authentication protection of a different tenant. This crossing of the tenant boundary is the basis for the scope-changed vector. At time of publication, there are no publicly available patches.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Improper Restriction of Excessive Authentication Attempts
The product does not implement sufficient measures to prevent multiple failed authentication attempts within a short time frame.
How developers prevent this class of flaw
- Common protection mechanisms include: Disconnecting the user after a small number of failed attempts Implementing a timeout Locking out a targeted account Requiring a computational task on the user's part.
- Use a vetted library or framework that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid. Consider using libraries with authentication capabilities such as OpenSSL or the ESAPI Authenticator.
More Improper Restriction of Excessive Authentication Attempts vulnerabilities (CWE-307)
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: partial).
- Record last changed materially (score, affected products, status or references).
References
Advisories
Other vulnerabilities in appointment-booking-software
- 7.4 High severity
- 8.3 High severity
- 9.8 Critical severity
- 9.4 Critical severity
- 9.8 Critical severity
- 9.9 Critical severity
Recent Improper Restriction of Excessive Authentication Attempts vulnerabilities
- 8.2 High severity
- 7.4 High severity
- 7.4 High severity
- 7.5 High severity
- 8.1 High severity
- 8.1 High severity
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