2026-010: Critical Vulnerabilities in Citrix NetScaler ADC and NetScaler Gateway

2026-010: Critical Vulnerabilities in Citrix NetScaler ADC and NetScaler Gateway ↗ source

August 19, 2026 CERT-EU Advisory

Source: https://cert.europa.eu/publications/security-advisories/2026-010/

Summary

The vulnerability CVE-2026-19489 (CVSS: 8.8) is a memory overflow vulnerability that can lead to unpredictable behaviour or Denial of Service. The vulnerability CVE-2026-19490 (CVSS: 9.3) is an authentication bypass using an alternate The following supported versions of NetScaler ADC and NetScaler Gateway are affected: The vulnerability CVE-2026-19489 requires SIP ALG(Session Initiation Protocol Application Layer Gateway) to be enabled on a Large Scale NAT (LSN) group configuration. Customers can determine if the appliance meets the precondition by inspecting their NetScaler configuration for the specified string: The vulnerability CVE-2026-19490 requires the appliance to be configured as a Gateway (SSL VPN, ICA Proxy, CVPN, RDP Proxy) or an AAA virtual server. On versions 14.1-43.56 or later and 13.1-61.28 or later, the issue is applicable only when a SAML action is configured; on earlier builds and 13.1 FIPS, Gateway or AAA virtual server configuration is sufficient. Customers can determine if the appliance meets the precondition by inspecting their NetScaler configuration for the specified string: add authentication samlAction.

News Coverage

Date	Source	Article
2026-09-04	BleepingComputer	Critical Citrix NetScaler auth bypass now leveraged in attacks CVE-2026-19490
2026-08-24	Check Point Research	24th August – Threat Intelligence Report CVE-2026-19489

Articles from the monitored vendor research blogs and security news feeds that reference a CVE cited in this publication, or name the campaign it covers. Coverage begins when feed monitoring started; earlier articles are not indexed.

CVEs Referenced in This Publication

CVE	CVSS	Affected
CVE-2026-19490	9.3 Critical	Citrix NetScaler Citrix NetScaler ADC and NetScaler Gateway contain an authentication-bypass vulnerability involving an alternate path or channel. When the NetScaler …
CVE-2026-19489	8.8 High	NetScaler ADC 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.…

Extracted from the publication text. Each CVE links to its tracked detail page.

Vendors Named in This Publication

Citrix 24 KEV

Each vendor links to its Known Exploited Vulnerabilities catalog page. Only vendors that appear in the KEV catalog are listed, either because the publication cites one of their KEV entries or because it names them directly.