October 18, 2023 · Applied Cybernetics Group
CVE-2023-4966 — Citrix NetScaler ADC and NetScaler Gateway
known ransomware use
Citrix NetScaler ADC and NetScaler Gateway Buffer Overflow Vulnerability
- Added to KEV
2023-10-18- Federal due date
2023-11-08- Vendor
- Citrix
- Product
- NetScaler ADC and NetScaler Gateway
- EPSS
- 100.0th percentile (score 0.943, as of
2026-06-08) - NVD CVSS v3.1
- —
- Ransomware use
- Known
- Upstream
- https://nvd.nist.gov/vuln/detail/CVE-2023-4966
CISA short description
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.
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.