# CVE-2023-6549: Citrix NetScaler ADC and NetScaler Gateway Buffer Overflow Vulnerability

Source: https://junglewise.ai/threats/cve-2023-6549-citrix-netscaler-adc-and-netscaler-gateway-buffer-overflow  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2024-01-17. Updated: 2026-05-09  
License: CC BY 4.0 with a link back

CVE-2023-6549 · Severity: critical · CVSS 8.2 · Exploited in the wild · Published 2024-01-17

A buffer overflow vulnerability in Citrix NetScaler ADC and NetScaler Gateway allows an unauthenticated attacker to cause a denial-of-service (DoS) or perform an out-of-bounds memory read. The vulnerability is exploitable when the device is configured as a Gateway 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-2023-6549 exploited in the wild?** Yes. CVE-2023-6549 is known to be exploited in the wild, first recorded on 17 January 2024. Treat it as urgent.

**How severe is CVE-2023-6549?** Critical severity, with a CVSS score of 8.2, published 17 January 2024.

**Which products and versions are affected?** Citrix NetScaler ADC 13.0 before 13.0-92.21, 13.1 before 13.1-51.15, 14.1 before 14.1-12.35, 12.1-FIPS before 12.1-55.302, 13.1-FIPS before 13.1-37.176, 12.1-NDcPP before 12.1-55.302; Citrix NetScaler Gateway 13.0 before 13.0-92.21, 13.1 before 13.1-51.15, 14.1 before 14.1-12.35.

**Is there a fix for CVE-2023-6549?** 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-2023-6549 attacked?** It is attacked over the network, in a network appliance.

**Am I affected by CVE-2023-6549?** 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 NetScaler ADC 13.0 before 13.0-92.21, 13.1 before 13.1-51.15, 14.1 before 14.1-12.35, 12.1-FIPS before 12.1-55.302, 13.1-FIPS before 13.1-37.176, 12.1-NDcPP before 12.1-55.302
- Citrix NetScaler Gateway 13.0 before 13.0-92.21, 13.1 before 13.1-51.15, 14.1 before 14.1-12.35

## Timeline

- 2024-01-17: disclosed
- 2024-01-17: kev added: Added to CISA KEV catalog due to active exploitation.
- 2024-01-17: advisory: Citrix security bulletin CTX584986 published.

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- [Citrix NetScaler memory overflow in KBA authentication](https://junglewise.ai/threats/cve-2026-111340-memory-overflow-in-kba-knowledge-based-authentication-can-lead)
- [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)
- [Citrix NetScaler ADC memory overflow in WebAuth authentication](https://junglewise.ai/threats/cve-2026-107414-memory-overflow-in-webauth-authentication-can-lead-to)