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…
Published: 2026-07-27 · CVSS: 6.1 · CVSS 3.1
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 Schedule Appointments WordPress plugin before 1.6.12.4's wp_kses_post() filter, so a double-encoded payload survives intake and is reintroduced as an executable element at render time.
Source: CVE Program · Revision 8b16575c39f1e1810c5e863010da073d2d3285e7