Citrix NetScaler Authentication Bypass Using an Alternate Path or Channel Vulnerability

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• cpe citrix/netscaler application delivery controllerversion unspecified
• cpe citrix/netscaler gatewayversion unspecified
• vendor Citrix NetScalerversion unspecified
• vendor Citrix NetScaler ADC and NetScaler Gatewayversion unspecified

How to fix CVE-2026-19490

• Recommended 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. CISA due date Sep 12, 2026.

• Official advisories

  • CISA KEV · cisa.gov
  • CVE.org · cve.org
  • FIRST EPSS · first.org
  • NIST NVD · nvd.nist.gov
  • Rapid7 Vulnerability Database · rapid7.com
  • VulnCheck KEV · vulncheck.com

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

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.

1. Aug 19, 2026 · Catalog

   Detected

   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.

2. Sep 9, 2026 · CISA KEV

   Known exploited

   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

3. Sep 12, 2026 · CISA KEV

   Remediation due

   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

4. Oct 7, 2026 · Catalog

   Updated

   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.

Sources

• CISA KEVConfirmed exploitationCVE-2026-19490

  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.

  cisa.gov
• CVE.orgVulnerability recordCVE-2026-19490

  Official CVE identifier

  cve.org
• FIRST EPSSExploitation probabilityCVE-2026-19490

  30-day exploitation probability 23.2%

  first.org
• NIST NVDVulnerability recordCVE-2026-19490

  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.

  nvd.nist.gov
• Rapid7 Vulnerability DatabaseResearchCVE-2026-19490

  Overview On August 19, 2026, a security advisory was published for CVE-2026-19490 , a critical authentication bypass vulnerability affecting Citrix NetScaler ADC and NetScaler Gateway. The vulnerability carries a CVSS v4.0 base score of 9.3 and can be exploited remotely by an unauthenticated attacker over the network without user interaction or elevated privileges. NetScaler ADC and NetScaler Gate

  rapid7.com
• VulnCheck KEVConfirmed exploitationCVE-2026-19490

  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 remot

  vulncheck.com

References

• CISA note · nvd.nist.gov
• VulnCheck exploitation evidence · previdian.com
• CISA note · support.citrix.com
• Vendor Advisory · support.citrix.com
• US Government Resource · cisa.gov
• CISA note · cisa.gov
• CISA note · cisa.gov
• VulnCheck exploitation evidence · cisa.gov

Freshness

Last verified in this catalog Oct 18, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.