Risk Letters

Exploited vulnerability

CVE-2026-19490

TLP:CLEAR

Citrix NetScaler Authentication Bypass Using an Alternate Path or Channel Vulnerability

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.

Facts

  • Vendor: Citrix
  • Product: NetScaler
  • CVSS: 9.3
  • EPSS (probability of exploitation within 30 days): 32.7 %
  • On CISA's Known Exploited Vulnerabilities list since: 9 September 2026
  • First known exploitation: 9 September 2026
  • CISA's deadline for US federal agencies: 12 September 2026
  • Weakness: CWE-288
  • First seen by Risk Letters: 9 September 2026

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Data: NVD (public domain), CISA KEV, FIRST EPSS, MITRE ATT&CK, AlienVault OTX. NVD