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Appointment Booking Calendar <= 1.6.11.11 — Incorrect Authorization to Unauthenticated Sensitive Field Modification via Appointment Public Token

CVE-2026-6723Published · Updated

Action summary

Affected: ≤1.6.11.11Update to 1.6.12.0 or newer

All remediation steps
Severity
Medium5.3
CVSS
5.3
CVSS 3.1 · CNA (Wordfence)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
What does this vector mean?
AV:N Attack vector
Network
AC:L Attack complexity
Low
PR:N Privileges required
None
UI:N User interaction
None
S:U Scope
Unchanged
C:N Confidentiality
None
I:L Integrity
Low
A:N Availability
None
Weakness
CWE-863 Incorrect Authorization
Required access
No account needed
Exploit prediction (EPSS)
No score
CISA KEV
Not listed

Am I affected?

Simply Schedule Appointments simply-schedule-appointments

  1. Affected≤ 1.6.11.11
  2. Patched in1.6.12.0

Update to 1.6.12.0 or newer.

You are affected if you run ≤ 1.6.11.11. Version 1.6.12.0 and later are not affected by this issue.

  • Check your version: in wp-admin go to Plugins → Installed Plugins and read the version under Simply Schedule Appointments.
  • No admin access? Run a passive check of your site. It reads public files only.
  • No account is needed to exploit this. Treat any exposed site on an affected version as at risk.

What to do

  1. Update to version 1.6.12.0, or a newer patched version
  2. Rotate administrator passwords and application secrets if the site ran a vulnerable version while publicly reachable.
  3. Watch Simply Schedule Appointments to get an email when the next vulnerability is published.

Advisory

Source description from Wordfence Intelligence, credited to awhacken.

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.

Exploits & references

Proof-of-concept & detection

No public proof-of-concept or detection template is known for this vulnerability.

Advisories & patches

More in Simply Schedule Appointments

All 52
More vulnerabilities in Simply Schedule Appointments
SeverityVulnerabilityCVEPublished
Medium5.3Missing Authorization
≤1.6.13.0Update to 1.6.13.4
CVE-2026-125437
High7.2Unauthenticated Stored Cross-Site Scripting
≤1.6.12.35Update to 1.6.12.37
CVE-2026-110382
Medium4.3Authenticated (Contributor+) Insecure Direct Object Reference
≤1.6.12.35Update to 1.6.12.37
CVE-2026-110381
High7.2Unauthenticated Stored Cross-Site Scripting via 'status' Parameter via /wp-json/ssa/v1/appointments/{id}
≤1.6.12.35Update to 1.6.12.37
CVE-2026-104000
Medium6.5Insecure Direct Object Reference to Authenticated (Subscriber+) Sensitive Information Disclosure via 'complete_group' Parameter
≤1.6.12.31Update to 1.6.12.33
CVE-2026-91109

Timeline

  1. CVE published

    Severity medium, CVSS 5.3

  2. Record last updated

Sources & licenses

Wordfence record
Vulnerability data
Wordfence Intelligence. [object Object] Licensed under the CC BY-SA 4.0.
CVE® identifiers
[object Object]. Used under the CVE Program. CVE® is a registered trademark of The MITRE Corporation.
CVSS / CWE
National Vulnerability Database (NVD), shown unmodified. This product uses the NVD API but is not endorsed or certified by the NVD.
VulnCrest content
Summary, remediation guidance and page layout © VulnCrest. Not sourced from NVD.

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