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Citrix · NetScaler ADC and NetScaler Gateway

CVE-2023-6549

Citrix NetScaler ADC and NetScaler Gateway Buffer Overflow Vulnerability

CISA KEV record

CISA date added
2024-01-17
CISA due date
2024-02-07
Known ransomware use
Unknown

NVD risk context

7.5 HIGH

CVSS is a technical severity score. CISA’s KEV status remains the evidence that this vulnerability is known to be exploited.

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Attack vector
Network
The vulnerable service can be reached remotely over a network.
Attack complexity
Low
Exploitation does not require unusual conditions beyond normal attacker control.
Privileges required
None
The attacker does not need an existing account or privileges.
User interaction
None
No action by another user is required.

Description

Citrix NetScaler ADC and NetScaler Gateway contain a buffer overflow vulnerability that allows for a denial-of-service when configured as a Gateway (VPN virtual server, ICA Proxy, CVPN, RDP Proxy) or AAA virtual server.

Required action

Apply mitigations per vendor instructions or discontinue use of the product if mitigations are unavailable.

NVD reference index

Vendor and remediation references

NVD has tagged these sources as vendor advisories, patches, mitigations, or release notes.

Other NVD references (1)

MITRE CWE context

CWE classification

CWE-119 Improper Restriction of Operations within the Bounds of a Memory Buffer

The product performs operations on a memory buffer, but it reads from or writes to a memory location outside the buffer's intended boundary. This may result in read or write operations on unexpected memory locations that could be linked to other variables, data structures, or internal program data.

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NVD record timing

NVD record timeline

These dates describe NVD’s record, not CISA’s KEV addition or remediation due date.

NVD published
Jan 17, 2024, 09:15 PM UTC
When NVD first published this CVE record.
NVD last updated
Jun 17, 2026, 06:50 AM UTC
When NVD last changed its analysis or record data.
Advanced: view the technical CVSS vector

This standardized code is intended for security tools and technical analysts. The plain-language risk summary above explains its main points.

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

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CISA notes

https://support.citrix.com/article/CTX584986/netscaler-adc-and-netscaler-gateway-security-bulletin-for-cve20236548-and-cve20236549; https://nvd.nist.gov/vuln/detail/CVE-2023-6549