CVE-2026-13400 Simply Schedule Appointments < 1.6.12.4 - Unauthenticated Stored XSS via Booking Customer Information

Simply Schedule Appointments is vulnerable to unauthenticated Stored Cross-Site Scripting in all versions up to and including 1.6.12.2. The root cause is a sanitization-ordering defect: the rendered notification content is decoded back into live HTML after it has already passed through the Simply...