What is CVE-2023-6549?

CVE-2023-6549 is a high-severity vulnerability in Citrix Netscaler Application Delivery Controller, classified under Improper Restriction of Operations within the Bounds of a Memory Buffer. CVSS score: 8.2/10. Published 2024-01-17.

How severe is CVE-2023-6549?

High severity. CVSS v3 base score is 8.2 out of 10.

Is CVE-2023-6549 known to be exploited?

Yes. CVE-2023-6549 is listed in the CISA Known Exploited Vulnerabilities catalog (added 2024-01-17), indicating it is being actively exploited. 4 public proof-of-concept repositories are indexed.

Buffer overflow in Citrix Netscaler Application Delivery Controller

CVE-2023-6549

Improper Restriction of Operations within the Bounds of a Memory Buffer in NetScaler ADC and NetScaler Gateway allows Unauthenticated Denial of Service and Out-Of-Bounds Memory Read

Vulnerability class: Buffer Overflow

Published 2024-01-17 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 8.2 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:H.

EPSS exploit prediction

EPSS: 0.576 (99.1th percentile), scored 2026-10-18.

High probability of exploitation in the next 30 days — patch promptly. 99th percentile — 99.1% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.576 · newest: 0.576 · change: 0.000

Affected products

Citrix Netscaler Application Delivery Controller
Citrix Netscaler Gateway
Cloud Software Group Netscaler Adc — versions 14.1, 13.1, 13.0

Weakness classification (CWE)

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

CISA KEV (Known Exploited Vulnerabilities)

This CVE is on the CISA KEV catalog, added on 2024-01-17. CISA KEV inclusion means CISA has confirmed in-the-wild exploitation; US federal agencies are required to remediate within a published due date.

BOD 22-01 due date: 2024-02-07.

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

Public proof-of-concept exploits

References

support.citrix.com/article/CTX584986/netscaler-adc-and-netscaler-gateway-securi… (Vendor Advisory)
134c704f-9b21-4f2e-91b3-4a467353bcc0 (US Government Resource)

Frequently asked questions

What is CVE-2023-6549?: CVE-2023-6549 is a high-severity vulnerability in Citrix Netscaler Application Delivery Controller, classified under Improper Restriction of Operations within the Bounds of a Memory Buffer. CVSS score: 8.2/10. Published 2024-01-17.
How severe is CVE-2023-6549?: High severity. CVSS v3 base score is 8.2 out of 10.
Is CVE-2023-6549 known to be exploited?: Yes. CVE-2023-6549 is listed in the CISA Known Exploited Vulnerabilities catalog (added 2024-01-17), indicating it is being actively exploited. 4 public proof-of-concept repositories are indexed.