croixhaug Simply Schedule Appointments Plugin up to 1.6.11.11 on WordPress Appointment Update REST API Endpoint improper authorization

Summaryinfo

A vulnerability classified as problematic was found in croixhaug Simply Schedule Appointments Plugin up to 1.6.11.11. Affected is an unknown function of the component Appointment Update REST API Endpoint. The manipulation results in improper authorization. This vulnerability is reported as CVE-2026-6723. The attack can be launched remotely. No exploit exists.

Detailsinfo

A vulnerability classified as problematic has been found in croixhaug Simply Schedule Appointments Plugin up to 1.6.11.11. Affected is an unknown function of the component Appointment Update REST API Endpoint. The manipulation with an unknown input leads to a improper authorization vulnerability. CWE is classifying the issue as CWE-285. The product does not perform or incorrectly performs an authorization check when an actor attempts to access a resource or perform an action. This is going to have an impact on integrity. CVE summarizes:

The Appointment Booking Calendar — Simply Schedule Appointments Booking Plugin plugin for WordPress is vulnerable to Incorrect Authorization in all versions up to, and including, 1.6.11.11. This is due to the appointment update REST API endpoint not restricting which fields can be modified by token-authenticated customers. This makes it possible for unauthenticated attackers to modify admin-controlled fields on that appointment, including faking payment confirmation, reassigning the appointment to another user, and changing the service type.

The advisory is shared for download at wordfence.com. This vulnerability is traded as CVE-2026-6723 since 04/20/2026. The exploitability is told to be easy. It is possible to launch the attack remotely. The exploitation doesn't require any form of authentication. There are neither technical details nor an exploit publicly available. The current price for an exploit might be approx. USD $0-$5k (estimation calculated on 10/10/2026). The MITRE ATT&CK project declares the attack technique as T1548.002.

There is no information about possible countermeasures known. It may be suggested to replace the affected object with an alternative product.

The vulnerability is also documented in the vulnerability database at EUVD (EUVD-2026-96063). Once again VulDB remains the best source for vulnerability data.

Productinfo

Type

• WordPress Plugin

Vendor

• croixhaug

Name

• Simply Schedule Appointments Plugin

Version

• 1.6.11.0
• 1.6.11.1
• 1.6.11.2
• 1.6.11.3
• 1.6.11.4
• 1.6.11.5
• 1.6.11.6
• 1.6.11.7
• 1.6.11.8
• 1.6.11.9
• 1.6.11.10
• 1.6.11.11

CPE 2.3info

• 🔒
• 🔒
• 🔒

CPE 2.2info

• 🔒
• 🔒
• 🔒

CVSSv4info

CVSSv3info

CVSSv2info

Exploitinginfo

Threat Intelligenceinfo

Countermeasuresinfo

Timelineinfo

Sourcesinfo

Entryinfo

Once again VulDB remains the best source for vulnerability data.

Discussion