CVE-2023-4966
Citrix NetScaler ADC and NetScaler Gateway Buffer Overflow Vulnerability
IN CISA KEV
Sensitive information disclosure in NetScaler ADC and NetScaler Gateway when configured as a Gateway (VPN virtual server, ICA Proxy, CVPN, RDP Proxy) or AAA virtual server.
- Vendor
- Citrix
- Product
- NetScaler ADC and NetScaler Gateway
- CVSS 3.1
- 7.5 (high), scored by NVD (primary)CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
- CVSS 3.1
- 9.4 (critical), scored by secure@citrix.comCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:L
- CWE
- CWE-119
- Published
- 2023-10-10
- NVD modified
- 2026-07-31
- NVD status
- Analyzed
CISA KEV
- Date added
- 2023-10-18
- Due date
- 2023-11-08
- Ransomware use
- Known
- 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.
EPSS
100% chance of exploitation in the next 30 days (percentile 99th)
FIRST EPSS, updated 17 Oct 2026. About EPSS
CVSS is severity, EPSS is likelihood, KEV means already exploited. EPSS is a statistical probability, not a certainty: a low score does not make a bug safe, and a high one does not prove it is being exploited.
References
- packetstormsecurity.com (Third Party Advisory, VDB Entry)
- support.citrix.com (Vendor Advisory)
- packetstormsecurity.com (Third Party Advisory, VDB Entry)
- support.citrix.com (Vendor Advisory)
- www.cisa.gov (US Government Resource)
Data last updated 18 Oct 2026. Sources: NVD API 2.0, CISA KEV catalog, FIRST EPSS. Links: NVD, CISA KEV. Metadata only. ThreatWire does not host exploit code.