Actively exploited
Listed in CISA’s Known Exploited Vulnerabilities catalog since October 18, 2023.
CVE-2023-4966
Citrix NetScaler ADC and NetScaler Gateway Buffer Overflow Vulnerability
Citrix · NetScaler ADC and NetScaler Gateway
Added to KEV October 18, 2023
Alert details
- Source feed
- CISA KEV
- CVE ID
- CVE-2023-4966
- CWE
- CWE-119
- Affected products
- NetScaler ADC and NetScaler Gateway · Citrix NetScaler ADC and NetScaler Gateway · Citrix
What happened
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 it means for your business
Citrix NetScaler ADC and NetScaler Gateway is listed in CISA's Known Exploited Vulnerabilities catalog (CVE-2023-4966). 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. CISA remediation due date: 2023-11-08. If you need help checking exposure, call (864) 335-9223.
Required action
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.
CISA due date: November 8, 2023
Sources
Related briefs
Citrix NetScaler Improper Restriction of Operations within the Bounds of a Memory Buffer Vulnerability
Citrix NetScaler is listed in CISA's Known Exploited Vulnerabilities catalog (CVE-2026-88779). Citrix NetScaler ADC (formerly Citrix ADC) and Citrix NetScaler Gateway (formerly Citrix Gateway) contain an improper restriction of operations within the bounds of a memory buffer vulnerability that could allow for a denial of service. CISA remediation due date: 2026-10-07. If you need help checking exposure, call (864) 335-9223.
Citrix NetScaler Improper Restriction of Operations within the Bounds of a Memory Buffer Vulnerability
Citrix NetScaler is listed in CISA's Known Exploited Vulnerabilities catalog (CVE-2026-88772). Citrix NetScaler ADC and NetScaler Gateway contain an improper restriction of operations within the bounds of a memory buffer vulnerability that could allow for remote code execution or denial of service CISA remediation due date: 2026-09-30. If you need help checking exposure, call (864) 335-9223.
Citrix NetScaler Improper Input Validation Vulnerability
Citrix NetScaler is listed in CISA's Known Exploited Vulnerabilities catalog (CVE-2026-88771). Citrix NetScaler ADC and NetScaler Gateway contain an improper input validation vulnerability that could allow an unauthenticated attacker to execute arbitrary commands. CISA remediation due date: 2026-09-30. If you need help checking exposure, call (864) 335-9223.
Citrix NetScaler Authentication Bypass Using an Alternate Path or Channel Vulnerability
Citrix NetScaler is listed in CISA's Known Exploited Vulnerabilities catalog (CVE-2026-19490). 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. CISA remediation due date: 2026-09-12. If you need help checking exposure, call (864) 335-9223.
Need help patching?
PremierePC monitors KEV alerts for managed clients and helps teams prioritize remediation before attackers do.