CVE-2023-4966

Unauthenticated sensitive information disclosure

Critical 9.4
Exploited: added to CISA KEV 18 Oct 2023
Used in ransomware campaigns

Description

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.

Key facts

Published: 10 Oct 2023
Last changed: 31 Jul 2026
Assigned by: Citrix
KEV added: 18 Oct 2023
KEV fix due: 8 Nov 2023
Used in ransomware: Yes, according to CISA
EPSS: 99.999% likely to be exploited in the next 30 days, higher than 99.997% of CVEs (scores for 15 Nov 2026)
SSVC (CISA): Exploitation: active; Automatable: yes; Technical impact: total

Severity scores

Each score is shown as its source gave it. They are not averaged or merged.

9.4CVSS 3.1, Criticalfrom the CNA (Citrix)CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:L

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.CISA KEV required action

Historical context and remediation

This reference retains the original CVE publication date. A recent record update does not mean a new attack occurred.

No separately sourced impact summary is available on this page yet. Consult the description, version data and dated exploitation evidence.

Version statuses below come from the CNA. An “unaffected” version is not necessarily a currently supported release or proof of a patch date. EPSS is a dated risk estimate, not a count of historical attacks.

Read the original CVE record.

Affected products

Vendor	Product	Versions
Citrix	NetScaler ADC	Default status: unaffected 14.1 up to but excluding 8.50 (affected) 13.1 up to but excluding 49.15 (affected) 13.0 up to but excluding 92.19 (affected) 13.1-FIPS up to but excluding 37.164 (affected) 12.1-FIPS up to but excluding 55.300 (affected) 12.1-NDcPP up to but excluding 55.300 (affected)
Citrix	NetScaler Gateway	Default status: unaffected 14.1 up to but excluding 8.50 (affected) 13.1 up to but excluding 49.15 (affected) 13.0 up to but excluding 92.19 (affected)