[KEV] Buffer Overflow in Citrix NetScaler ADC and NetScaler Gateway (CVE-2023-4966)
Summary
Vulnerability in Citrix NetScaler ADC and NetScaler Gateway (CVE-2023-4966). Confidential information can be exposed externally. Listed in CISA KEV — actively exploited.
Original description
The description as published by the source.
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.
Auto-generated summary
Assembled by SecPulse from the source data (CVSS, CWE, affected versions) using templates — no AI involved. Check the original description and references below for exact details.
A vulnerability tracked as CVE-2023-4966 has been found in Citrix NetScaler ADC and NetScaler Gateway.
Confidential information can be exposed externally. CVSS score: 9.4/10.
Note: CISA has officially confirmed this is actively exploited in the wild. Treat it with elevated urgency.
What to do: apply the vendor's official patched release.
If unsure, ask your IT team or search "Citrix NetScaler ADC and NetScaler Gateway CVE-2023-4966" on the vendor's site.
CVE-2023-4966 (Citrix NetScaler ADC and NetScaler Gateway) — CWE-119 / CVSS v3 9.4
Attack vector: remote (network-reachable) / unauthenticated / no user interaction
Listed in CISA KEV — actively exploited, treat as top priority.
Plan: 1) Audit SBOM/dependencies, 2) Stage→prod upgrade, 3) Add WAF/proxy monitoring on affected endpoints, 4) Hunt IOCs in logs.
Refs: see the GHSA / vendor advisory / patched release linked on this page.
A vulnerability (CWE-119) exists in Citrix NetScaler ADC and NetScaler Gateway.
Check the vendor advisory for the affected versions of Citrix NetScaler ADC and NetScaler Gateway.
Severity: Critical (CVSS 9.4/10). Confidential information can be exposed externally. Listed in CISA KEV — actively exploited in the wild, treat as top priority.
Update to the patched release per vendor advisory.
Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.
Search webserver/proxy logs for unusual request patterns matching this CVE's known IOCs. Audit SBOM/dependencies to find affected services.
Response actions
Concrete steps and command examples for SOC/SRE teams to execute in order
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1Identify exposure identify
Audit SBOM/dependencies for affected components.資産台帳・SBOM・依存マニフェストで Citrix NetScaler ADC and NetScaler Gateway を使っているサービスとバージョンを洗い出す。
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2Consider incident declaration escalate
Notify SOC / on-callCISA KEV登録済 = 実環境で悪用が観測されている。侵入の兆候があればインシデント対応宣言、無くてもパッチ適用までWAF強化を最優先で。
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3Post-deployment verification verify
Confirm patched version is live in productionパッチ適用後、ステージングで PoC または同等の悪用パターンを再現して脆弱性が閉じたことを確認。本番ではアクセスログ・WAF でアラート再発が無いか継続監視。
References
- advisory NVD
- advisory packetstormsecurity.com
- patch support.citrix.com
- web cisa.gov