CVE-2026-13400 - Before 1 Plugin
CVE-2026-13400
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
UNKNOWN
CVSS 0.0
Published 2026-07-27
Updated 2026-07-27
AI Risk Low (6/100)
Active Exploit: No strong signal
Published Exploit: No public exploit references
Priority: P5 Monitor
Severity Band
UNKNOWN
CVSS Vector
Unspecified
Affected Components
2
Reference Links
1
AI Risk Engine
Low (6/100)
Exploitability
Low
Active Exploitation
No strong signal
Published Exploit Status
No public exploit references
AI Context
Machine-generated threat intelligence
AI
Updated just now
AI enriched just now (2026-07-27 20:15 UTC)
Technical Summary
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.
Potential Impact
Severity is UNKNOWN (CVSS 0.0). Depending on deployment context, affected components may be exposed to unauthorized actions or data integrity risk.
Exploitability Assessment
Exploitability is assessed as Low based on low-bar exploit prerequisites.
Primary risk drivers: low-bar exploit prerequisites
Mitigation Recommendations
Validate affected product versions, prioritize patching, and monitor references for vendor remediation guidance. If immediate patching is not possible, apply compensating controls and limit exposure of vulnerable surfaces.
Detection & Monitoring
Track authentication anomalies, unexpected file writes, and suspicious plugin API activity around affected components.
Business Impact Lens
AI risk score 6/100 (Low, Low) with priority P5 Monitor. Prioritize remediation where affected components process customer data, admin sessions, or Internet-exposed workflows.