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PatchSiren cyber security CVE debrief

CVE-2026-39447 NSquared CVE debrief

A high-severity Unauthenticated Cross Site Scripting (XSS) vulnerability was discovered in Simply Schedule Appointments plugin versions <= 1.6.10.6. The vulnerability has a CVSS score of 7.1 and is considered HIGH. It allows unauthenticated attackers to inject malicious scripts into the application.

Vendor
NSquared
Product
Simply Schedule Appointments
CVSS
HIGH 7.1
CISA KEV
Not listed in stored evidence
Original CVE published
2026-06-15
Original CVE updated
2026-06-15
Advisory published
2026-06-15
Advisory updated
2026-06-15

Who should care

Administrators and users of Simply Schedule Appointments plugin versions <= 1.6.10.6 should apply the necessary patches to prevent exploitation.

Technical summary

The vulnerability is caused by a lack of proper input validation and sanitization in the Simply Schedule Appointments plugin. This allows unauthenticated attackers to inject malicious scripts into the application, potentially leading to sensitive information disclosure or other malicious activities.

Defensive priority

HIGH

Recommended defensive actions

  • Apply the latest patch or update to Simply Schedule Appointments plugin version > 1.6.10.6
  • Review and restrict user input to prevent malicious script injection

Evidence notes

Evidence of this vulnerability was provided by Patchstack, a reputable security research firm.

Official resources

CVE-2026-39447 was published on 2026-06-15T21:16:42.880Z and modified on 2026-06-15T21:24:32.790Z.