Memory Overflow in Citrix NetScaler Gateway and AAA vServers

An unauthenticated remote attacker may disrupt availability of an affected Gateway or AAA virtual server, causing service failure or other erroneous behavior. The CVSS v4 metrics indicate high availability impact, with low confidentiality and integrity impact.

Where immediate upgrading is not possible, reduce or remove external access to affected Gateway and AAA virtual servers and disable the affected service or virtual-server configuration where operationally feasible. Restrict administrative and client access through network controls, monitor appliance logs externally, and conduct compromise assessment and incident-response investigation for exposed appliances.

Upgrade every affected NetScaler ADC, NetScaler Gateway, and applicable Secure Private Access Hybrid NetScaler instance to the appropriate fixed build: 14.1-73.37 or later, 13.1-64.23 or later, 14.1-73.37 FIPS or later, or 13.1-37.279 FIPS/NDcPP or later. Verify the running build on every appliance node after upgrade. Assess externally exposed appliances for prior compromise and preserve relevant logs and forensic evidence before remediation where feasible; applying the update prevents further exploitation but does not remove artifacts or persistence from an earlier compromise.