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NetScaler ADC and NetScaler Gateway Security Bulletin for CVE-2026-19489 and CVE-2026-19490

Gedeon Richemond

2 min read

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NetScaler ADC and NetScaler Gateway Security Bulletin for CVE-2026-19489 and CVE-2026-19490

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Description of Problem

Multiple vulnerabilities have been discovered in NetScaler ADC (formerly Citrix ADC) and NetScaler Gateway (formerly Citrix Gateway). Refer below for further details.

 

Affected Versions

The following supported versions of NetScaler ADC and NetScaler Gateway are affected by the vulnerabilities: 

  • NetScaler ADC and NetScaler Gateway 14.1 BEFORE 14.1-73.32
  • NetScaler ADC and NetScaler Gateway 13.1 BEFORE 13.1-63.21
  • NetScaler ADC FIPS BEFORE 14.1-73.32 FIPS
  • NetScaler ADC FIPS and NDcPP BEFORE 13.1-37.277

Additional Note: Secure Private Access Hybrid deployments using NetScaler instances are also affected by the vulnerabilities. Customers need to upgrade these NetScaler instances to the recommended NetScaler builds to address the vulnerabilities. This bulletin only applies to customer-managed NetScaler ADC and NetScaler Gateway. Cloud Software Group upgrades the Citrix-managed cloud services and Citrix-managed Adaptive Authentication with the necessary software updates.

 


Summary

CVE-ID 		Description Pre-conditionsCWECVSSv4
CVE-2026-19489Memory overflow vulnerability leading to unpredictable behavior or Denial of ServiceSIP ALG(Session Initiation Protocol Application Layer Gateway) should be enabled on a Large Scale NAT (LSN) group configuration. CWE-119 – Improper Restriction of Operations within the Bounds of a Memory BufferCVSS v4.0 Base Score: 8.8(CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:H/SC:N/SI:N/SA:L)
CVE-2026-19490Authentication bypass using an alternate pathThe appliance must be configured as a Gateway (SSL VPN, ICA Proxy, CVPN, RDP Proxy) or an AAA virtual server, subject to the following version-specific requirements:

14.1-43.56 or later: Applicable only when configured with a SAML action.

14.1-43.55 or earlier: Applicable when configured with Gateway (SSL VPN, ICA Proxy, CVPN, RDP Proxy ) or AAA vserver

13.1-61.28 or later: Applicable only when configured with a SAML action.

13.1-61.27 or earlier: Applicable when configured with Gateway (SSL VPN, ICA Proxy, CVPN, RDP Proxy)  or AAA vserver

13.1 FIPS: Applicable when configured with Gateway (SSL VPN, ICA Proxy, CVPN, RDP Proxy) or AAA vserver.		CWE-288: Authentication Bypass Using an Alternate Path CVSS v4.0 Base Score: 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)
What Customers Should Do

Cloud Software Group strongly urges affected customers of NetScaler ADC and NetScaler Gateway to install the relevant updated versions as soon as possible. 

  • NetScaler ADC and NetScaler Gateway 14.1-73.32 and later releases
  • NetScaler ADC and NetScaler Gateway 13.1-63.21 and later releases of 13.1
  • NetScaler ADC 14.1-FIPS 14.1-73.32 FIPS and later releases of 14.1-FIPS
  • NetScaler ADC 13.1-FIPS and 13.1-NDcPP 13.1-37.277 and later releases of 13.1-FIPS and 13.1-NDcPP

Steps to determine if an appliance meets the CVE preconditions

For CVE-2026-19489:

Customers can determine if the appliance meets the precondition by inspecting their NetScaler configuration for the specified string:

  • “​add lsn group.*sipalg.*” 

For CVE-2026-19490: 

Customers can determine if the appliance meets the precondition by inspecting their NetScaler configuration for the specified string:

SAML action configuration

  • “add authentication samlAction.*“

 Auth or VPN vserver

  •  “add authentication vserver .*“

               Or 

  •  “add vpn vserver .*“
More Information

https://support.citrix.com/support-home/kbsearch/article?articleNumber=CTX696939&articleTitle=NetScaler_ADC_and_NetScaler_Gateway_Security_Bulletin_for_CVE_2026_19489_and_CVE_2026_19490