CVE-2026-13400: CWE-79 Cross-Site Scripting (XSS) in Simply Schedule Appointments
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.
CVE-2026-13400: CWE-79 Cross-Site Scripting (XSS) in Simply Schedule Appointments
Description
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.
CVSS v3.1
Score 6.1medium
Weaknesses
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- WPScan
- Date Reserved
- 2026-06-26T08:35:42.471Z
- Cvss Version
- null
- State
- PUBLISHED
- Remediation Level
- null
Threat ID: 6a66f9409c2644c7f888b44d
Added to database: 07/27/2026, 06:22:56 UTC
Last updated: 07/27/2026, 22:45:15 UTC
Views: 10
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