Citrix NetScaler ADC and NetScaler Gateway Buffer Overflow Vulnerability
Citrix — NetScaler ADC
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.
9.4
100.0%
Vector breakdown
- Attack vector
- Network
- Attack complexity
- Low
- Privileges required
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- High
- Availability
- Low
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:L
- Published
- Oct 10, 2023
- Modified
- Jul 31, 2026
- Added to KEV
- Oct 18, 2023
- Federal patch due
- Nov 8, 2023
CISA 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.
Weakness classification
Affected packages
Proof-of-concept & exploitation references
8 foundWeaponization
Public repositories whose name or description references CVE-2023-4966, found via a live GitHub search at request time. These are community-sourced signals, not a verified working exploit — cross-check each one before relying on it, and treat higher star counts and recent activity as (weak) corroboration, not proof.
- Chocapikk/CVE-2023-4966★ 78
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.
updated Oct 13, 2026
- RevoltSecurities/CVE-2023-4966★ 10
An Exploitation script developed to exploit the CVE-2023-4966 bleed citrix information disclosure vulnerability
updated Jan 17, 2026
- dinosn/citrix_cve-2023-4966★ 10
Citrix CVE-2023-4966 from assetnote modified for parallel and file handling
updated Sep 30, 2026
- mlynchcogent/CVE-2023-4966-POC★ 8
Proof Of Concept for te NetScaler Vuln
updated Oct 14, 2025
- certat/citrix-logchecker★ 5
Parse citrix netscaler logs to check for signs of CVE-2023-4966 exploitation
updated Mar 22, 2025
- morganwdavis/overread★ 2
Simulates CVE-2023-4966 Citrix Bleed overread bug
updated Apr 22, 2024
- IceBreakerCode/CVE-2023-4966★ 1
updated Sep 29, 2026
- akshthejo/CVE-2023-4966-exploit★ 0
CVE-2023-4966-exploit
updated Jan 17, 2025
References
Frequently asked questions
What is CVE-2023-4966?
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.
How severe is CVE-2023-4966?
CVE-2023-4966 has a CVSS base score of 9.4 out of 10 (CVSS 3.1).
Is CVE-2023-4966 actively exploited in the wild?
Yes. CVE-2023-4966 is listed in the CISA Known Exploited Vulnerabilities (KEV) catalog, added Oct 18, 2023, meaning CISA has confirmed evidence of active exploitation. It is also flagged as used in ransomware campaigns.
What is the EPSS score for CVE-2023-4966?
100.0% - meaning FIRST.org's EPSS model estimates a 100.0% probability this vulnerability will be exploited in the wild within 30 days (100% percentile among all scored CVEs).
Is there exploit tooling available for CVE-2023-4966?
Yes - a public Nuclei template referencing CVE-2023-4966 exist in public repositories we checked. We also found 8 public GitHub repositories referencing this CVE.
What type of vulnerability is CVE-2023-4966?
CVE-2023-4966 is classified under CWE-119 (CWE-119 Improper Restriction of Operations within the Bounds of a Memory Buffer).
Cross-checked against
Impactr finds and proves whether CVE-2023-4966 — or flaws like it — are actually reachable in your own web apps and APIs, with a reproducible exploit as evidence.