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[ CVE-2026-19490 · Published 19 Aug 2026 ]

Citrix NetScaler Authentication Bypass Using an Alternate Path or Channel Vulnerability

Exploited · CISA KEV CVSS 9.8 EPSS 23%No fix listed yet

[ Why it matters ]Priority signals

  • Exploited in the wild: on CISA's Known Exploited Vulnerabilities list since 2026-09-09
  • EPSS: 23% chance of exploitation in the next 30 days (higher than 98% of CVEs)
  • Critical severity: CVSS 9.8

[ Description ]Official description

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.

CISA: Citrix NetScaler ADC and NetScaler Gateway contain an authentication-bypass vulnerability involving an alternate path or channel. When the NetScaler appliance is configured as an AAA virtual server or as a Gateway (SSL VPN, ICA Proxy, CVPN, or RDP Proxy), an unauthenticated remote threat actor may be able to bypass authentication.

[ Fixes ]Fixes and patches

CISA required action (US federal deadline 12 Sep 2026): 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.

No fix or interim patch is linked from our sources yet. Check the vendor references below and limit exposure of affected systems until a fix is available.

[ References ]References