CVE-2023-4966Used in ransomware
Citrix NetScaler ADC and NetScaler Gateway
Citrix NetScaler ADC and NetScaler Gateway Buffer Overflow Vulnerability
What it is
Citrix NetScaler ADC and NetScaler Gateway contain a buffer overflow vulnerability that allows for sensitive information disclosure when configured as a Gateway (VPN virtual server, ICA Proxy, CVPN, RDP Proxy) or AAA virtual server.
What to do
Apply mitigations and kill all active and persistent sessions per vendor instructions [https://www.netscaler.com/blog/news/cve-2023-4966-critical-security-update-now-available-for-netscaler-adc-and-netscaler-gateway/] OR discontinue use of the product if mitigations are unavailable.
Vendor notices and references
- www.netscaler.com/blog/news/cve-2023-4966-critical-security-update-now-available-for-netsc
- nvd.nist.gov/vuln/detail/CVE-2023-4966
Description and required action as published by CISA. Full record at NVD.
Other Citrix entries on the list
- NetScaler Citrix NetScaler Improper Restriction of Operations within the Bounds of a Memory Buffer Vulnerability CVE-2026-88779 · Oct 4, 2026
- NetScaler Citrix NetScaler Improper Restriction of Operations within the Bounds of a Memory Buffer Vulnerability CVE-2026-88772 · Sep 27, 2026
- NetScaler Citrix NetScaler Improper Input Validation Vulnerability CVE-2026-88771 · Sep 27, 2026
- NetScaler Citrix NetScaler Authentication Bypass Using an Alternate Path or Channel Vulnerability CVE-2026-19490 · Sep 9, 2026
- NetScaler ADC and NetScaler Gateway Citrix NetScaler ADC and NetScaler Gateway Improper Restriction of Operations within the Bounds of a Memory Buffer Vulnerability CVE-2026-8452 · Aug 26, 2026
- NetScaler Citrix NetScaler Out-of-Bounds Read Vulnerability CVE-2026-3055 · Mar 30, 2026