CVE-2026-19490

Critical

Citrix NetScaler Authentication Bypass Using an Alternate Path or Channel Vulnerability

9.8 CVSS v3.1 CVSS v4.0: 9.3

Published: Aug 19, 2026
Updated: Oct 26, 2026
Vendor: Citrix
Affected versions: See affected products
Weakness: CWE-288

Summary

Vulnerability in NetScaler ADC and NetScaler Gateway.

This issue affects ADC: from 14.1 through 73.32 and from 13.1 through 63.21; Gateway: from 14.1 through 73.32 and from 13.1 through 63.21.

Severity

Critical (9.8)

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

CVSS v4.0 (9.3)

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:L/SI:L/SA:L/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Affected products

Citrix Netscaler Application Delivery Controller >= 13.1, < 13.1-37.277
Citrix Netscaler Application Delivery Controller >= 13.1, < 13.1-63.21
Citrix Netscaler Application Delivery Controller >= 14.1, < 14.1-73.32
Citrix Netscaler Application Delivery Controller >= 14.1-66.68, = 13.1, < 13.1-63.21
Citrix Netscaler Gateway >= 14.1, < 14.1-73.32

Exploitation status

Actively exploited

Listed in the CISA Known Exploited Vulnerabilities catalog on Sep 9, 2026. Federal remediation due: Sep 12, 2026.

Technical details

Technical analysis has not been written for this record yet.

Mitigation & remediation

Apply mitigations in accordance with vendor instructions, ensuring compliance with CISA’s BOD 26-04 Prioritizing Security Updates Based on Risk (see URL in Notes) guidance and CISA’s “Forensics Triage Requirements” (see URL in Notes). Follow applicable BOD 26-04 guidance for cloud services or discontinue use of the product if mitigations are unavailable. Stakeholders are responsible for evaluating each asset's internet exposure and ensuring adherence to BOD 26-04 patching guidelines.