Vulnerability · CVE-2026-39447
Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
Published Oct 13, 2026 · corrected/updated Oct 13, 2026 · NSquared Simply Schedule Appointments · evidence confidence very high
Unauthenticated Cross Site Scripting (XSS) in Simply Schedule Appointments <= 1.6.10.6 versions.
Grounded briefings
Catalog interpretations for three audiences. Each brief cites ingested metadata and the original advisories below. They are not independent research and they do not invent exploit steps.
Executive
CVE-2026-39447 is a unknown public vulnerability record for NSquared Simply Schedule Appointments. CISA lists it as known exploited. Published remediation guidance: Apply remediations or mitigations per vendor instructions or discontinue use of the product if remediation or mitigations are unavailable. This summary is a catalog interpretation of the ingested metadata and cites the original advisories below.
System administrator
Identify whether NSquared Simply Schedule Appointments is in your estate, then compare installed versions with the affected ranges. Affected packages or ranges on record: NSquared Simply Schedule Appointments. Published remediation guidance: Apply remediations or mitigations per vendor instructions or discontinue use of the product if remediation or mitigations are unavailable. Prefer the vendor or distribution advisory linked in Sources before changing production systems. This is a catalog interpretation, not a runbook.
Security analyst
Signals on file: EPSS 0.3%. CISA lists it as known exploited. Sources contributing to this record: epss, vulncheck_kev. Public exploit references, when present, are outbound links only and are not proof of active exploitation. This is a catalog interpretation of stored metadata.
Exploitation and remediation
Exploitation evidence
Confirmed in CISA KEV since Oct 13, 2026. Listed in CISA KEV and VulnCheck KEV.
Patch and remediation
Apply remediations or mitigations per vendor instructions or discontinue use of the product if remediation or mitigations are unavailable.
Safe detection guidance
Compare installed versions with the affected ranges below and verify the advisory from the original publisher. This site stores metadata and outbound links only; it does not ship exploit code or proof-of-concept payloads.
Code
The project this record applies to. Exploit listings stay in References.
No public source repository is identified for this product.
Timeline
Detection, updates, and resolution for this record.
Oct 13, 2026 · VulnCheck KEV
Detected
Unauthenticated Cross Site Scripting (XSS) in Simply Schedule Appointments <= 1.6.10.6 versions.
Oct 13, 2026 · CISA KEV
Known exploited
Apply remediations or mitigations per vendor instructions or discontinue use of the product if remediation or mitigations are unavailable.
Affected
- vendor NSquared Simply Schedule Appointmentsversion unspecified
Sources
- FIRST EPSSExploitation probabilityCVE-2026-39447
30-day exploitation probability 0.3%
first.org - VulnCheck KEVConfirmed exploitationCVE-2026-39447
Unauthenticated Cross Site Scripting (XSS) in Simply Schedule Appointments <= 1.6.10.6 versions.
vulncheck.com