CVE-2026-13358: Appointment Booking Calendar — Simply Schedule Appointments Booking Plugin <= 1.6.12.10 - Authenticated (Contributor+) Insecure Direct Object Reference to Sensi

Versions reported by the vendor

Affected version ranges reported by the assigning authority (Wordfence). Independent of NVD's CPE analysis and usually ahead of it.

• croixhaug Simply Schedule Appointments

  • up to and including 1.6.12.10affected · semver

Other highest-scoring records for the same primary product.

• CVE-2026-92245Simply Schedule Appointments <= 1.6.12.32 - Missing Authorization to Unauthenticated Sensitive Information Exposure and Arbitrary Appointment Deletion via 'recu
  30Monitor
• CVE-2026-89294Simply Schedule Appointments <= 1.6.12.27 - Authenticated (Subscriber+) Local File Inclusion via 'ssa_locale' Parameter
  30Monitor
• CVE-2026-104000Simply Schedule Appointments <= 1.6.12.35 - Unauthenticated Stored Cross-Site Scripting via 'status' Parameter via /wp-json/ssa/v1/appointments/{id}
  28Monitor

Published before and after this one in the same product

• Later →CVE-2026-91109Oct 1, 2026 · Simply Schedule Appointments <= 1.6.12.31 - Insecure Direct Object Reference to Authenticated (Subscriber+) Sensitive Information Disclosure via 'complete_group
  26Monitor
• Later →CVE-2026-6723Oct 10, 2026 · Appointment Booking Calendar <= 1.6.11.11 - Incorrect Authorization to Unauthenticated Sensitive Field Modification via Appointment Public Token
  21Monitor

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

Root cause

The endpoint fetches the record by the ID sent in the request, but never checks whether the record belongs to the requesting user.

A representative example of this vulnerability class. Not the vendor's source code; it shows the faulty pattern and its fix.

1const invoice = await Invoice.findById(req.params.id);2res.json(invoice);

1const invoice = await Invoice.findOne({2  id: req.params.id,3  ownerId: req.user.id,4});5if (!invoice) return res.sendStatus(404);6res.json(invoice);

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

MITRE has no CAPEC/ATT&CK mapping for this CWE.