Citrix NetScaler ADC and NetScaler Gateway Buffer Overflow Vulnerability
Cloud Software Group — NetScaler ADC
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
8.2
57.6%
Vector breakdown
- Attack vector
- Network
- Attack complexity
- Low
- Privileges required
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- None
- Integrity
- Low
- Availability
- High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:H
- Published
- Jan 17, 2024
- Modified
- Oct 21, 2025
- Added to KEV
- Jan 17, 2024
- Federal patch due
- Feb 7, 2024
CISA required action
Apply mitigations per vendor instructions or discontinue use of the product if mitigations are unavailable.
Weakness classification
Proof-of-concept & exploitation references
Weaponization
Public repositories whose name or description references CVE-2023-6549, 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.
No public GitHub repositories referencing CVE-2023-6549 were found at last check. Absence here is not proof no exploit exists - see the references below for vendor advisories and write-ups.
References
Frequently asked questions
What is 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
How severe is CVE-2023-6549?
CVE-2023-6549 has a CVSS base score of 8.2 out of 10 (CVSS 3.1).
Is CVE-2023-6549 actively exploited in the wild?
Yes. CVE-2023-6549 is listed in the CISA Known Exploited Vulnerabilities (KEV) catalog, added Jan 17, 2024, meaning CISA has confirmed evidence of active exploitation.
What is the EPSS score for CVE-2023-6549?
57.6% - meaning FIRST.org's EPSS model estimates a 57.6% probability this vulnerability will be exploited in the wild within 30 days (99% percentile among all scored CVEs).
Is there exploit tooling available for CVE-2023-6549?
Yes - a public Nuclei template referencing CVE-2023-6549 exist in public repositories we checked.
What type of vulnerability is CVE-2023-6549?
CVE-2023-6549 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-2023-6549 - or flaws like it - are actually reachable in your own web apps and APIs, with a reproducible exploit as evidence.
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