# CVE-2023-4966: Citrix NetScaler ADC and NetScaler Gateway Buffer Overflow Vulnerability

Source: https://junglewise.ai/threats/cve-2023-4966-citrix-netscaler-adc-and-netscaler-gateway-buffer-overflow  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2023-10-18. Updated: 2026-05-09  
License: CC BY 4.0 with a link back

CVE-2023-4966 · Severity: critical · CVSS 9.4 · Exploited in the wild · Published 2023-10-18

A buffer overflow vulnerability in Citrix NetScaler ADC and NetScaler Gateway allows for sensitive information disclosure. The flaw is exploitable when the devices are configured as a Gateway (VPN virtual server, ICA Proxy, CVPN, RDP Proxy) or AAA virtual server.

Technologies: [Citrix NetScaler ADC](https://junglewise.ai/threats/technologies/netscaler-adc), [Citrix NetScaler Gateway](https://junglewise.ai/threats/technologies/gateway). Vendors: [Citrix](https://junglewise.ai/threats/vendors/citrix).

## Quick answers

**Is CVE-2023-4966 exploited in the wild?** Yes. CVE-2023-4966 is known to be exploited in the wild, first recorded on 18 October 2023. Treat it as urgent.

**How severe is CVE-2023-4966?** Critical severity, with a CVSS score of 9.4, published 18 October 2023.

**Which products and versions are affected?** Citrix Systems, Inc. NetScaler ADC; Citrix Systems, Inc. NetScaler Gateway.

**Is there a fix for CVE-2023-4966?** No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.

**How is CVE-2023-4966 attacked?** It is attacked over the network, in a network appliance.

**Am I affected by CVE-2023-4966?** Check whether you run Citrix NetScaler ADC or Citrix NetScaler Gateway. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## Affected products

- Citrix Systems, Inc. NetScaler ADC
- Citrix Systems, Inc. NetScaler Gateway

## Timeline

- 2023-10-18: disclosed
- 2023-10-18: kev added: Added to CISA Known Exploited Vulnerabilities Catalog
- 2023-10-18: advisory: Vendor advisory CTX579459 published

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- [Citrix NetScaler ADC memory overflow in Email OTP authentication](https://junglewise.ai/threats/cve-2026-107415-memory-overflow-in-email-otp-authentication-can-lead-to)
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