CVE-2026-104000highCWE-79

CVE-2026-104000: high-severity vulnerability in croixhaug Simply Schedule Appointments

Simply Schedule Appointments <= 1.6.12.35 - Unauthenticated Stored Cross-Site Scripting via 'status' Parameter via /wp-json/ssa/v1/appointments/{id}

Published

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21Vexday Risk Score

No sign of exploitation. No public exploitation artifact known so far.

ssvc Trackcvss 7.2epss 0.2%
The Simply Schedule Appointments plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the 'status' parameter in all versions up to, and including, 1.6.12.35 due to insufficient input sanitization and output escaping. This makes it possible for unauthenticated attackers to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page. The malicious payload is stored unconditionally because debug logging is enabled by default, and the debug-log viewer is accessible to anyone holding the site-wide Support PIN (an HMAC-MD5 of AUTH_SALT displayed in wp-admin), meaning the injected script will execute against the administrator's session during ordinary support or troubleshooting workflows.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:N
Affected products
croixhaug · Simply Schedule Appointments
Related CVEs — croixhaug Simply Schedule Appointments

In the same product, most dangerous first.

CVE-2026-89294HIGHSimply Schedule Appointments <= 1.6.12.27 - Authenticated (Subscriber+) Local File Inclusion via 'ssa_locale' ParameterEPSS 1.0%CVE-2026-13358MEDIUMAppointment Booking Calendar — Simply Schedule Appointments Booking Plugin <= 1.6.12.10 - Authenticated (Contributor+) Insecure Direct Object Reference to Sensitive Information ExposureEPSS 0.7%CVE-2026-92245HIGHSimply Schedule Appointments <= 1.6.12.32 - Missing Authorization to Unauthenticated Sensitive Information Exposure and Arbitrary Appointment Deletion via 'recursive' Parameter on the appointment_types REST Endpoint via Public NonceEPSS 0.4%CVE-2026-91109MEDIUMSimply Schedule Appointments <= 1.6.12.31 - Insecure Direct Object Reference to Authenticated (Subscriber+) Sensitive Information Disclosure via 'complete_group' ParameterEPSS 0.3%CVE-2026-6723MEDIUMAppointment Booking Calendar <= 1.6.11.11 - Incorrect Authorization to Unauthenticated Sensitive Field Modification via Appointment Public TokenEPSS 0.2%