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Fencer Vulns
high 8.2

CVE-2023-6549 kev in the critical feed json

Improper Restriction of Operations within the Bounds of a Memory Buffer in NetScaler ADC and NetScaler Gateway allows Unauthenticated Denia…

published 2024-01-17 2 y ago modified 2026-06-17 4 mo ago also EUVD-2023-58779

cvss
8.2
version 3.1, CNA
cisa kev
Exploited
added 2024-01-17
epss
57.6%
EPSS 57.6% chance of exploitation in 30 days, percentile 99%
public exploits
0
none known, plus a Nuclei check

Summary

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

Patch / fix

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

  • Cloud Software Group NetScaler ADC 12.35, 37.176, 51.15, 55.302, 92.21

Timeline

  1. Added to CISA KEV
  2. Published
  3. CISA SSVC: exploitation active
  4. CISA patch deadline

Known exploited

Added
2 y ago
Patch by
2024-02-07 (2 y ago)
Ransomware
Not known
Required action
Apply mitigations per vendor instructions or discontinue use of the product if mitigations are unavailable.
Vendor, product
Citrix, NetScaler ADC and NetScaler Gateway
CISA name
Citrix NetScaler ADC and NetScaler Gateway Buffer Overflow Vulnerability

ATT&CK techniques

How it is exploited and what it leads to, in MITRE ATT&CK terms.

  • T1574 Hijack Execution Flow exploitation
  • T1499 Endpoint Denial of Service primary impact

kev release 2025-07-28, att&ck v16.1. KEV to ATT&CK mappings by the MITRE Center for Threat-Informed Defense (Mappings Explorer, Apache-2.0). © 2026 The MITRE Corporation. This work is reproduced and distributed with the permission of The MITRE Corporation. Terms of use

CISA SSVC

Exploitation
Active, exploited in the wild
Automatable
yes
Technical impact
partial
Assessed
2 y ago

Exploit prediction

57.63% chance of exploitation in the next 30 days, higher than 99% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • Nuclei template Citrix Netscaler ADC & Gateway - Out-Of-Bounds Memory Read nuclei detection template

CVSS scores

assigned by version score vector
CNA 3.1 8.2 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:H
NVD 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Affected products

  • Cloud Software Group NetScaler ADC

Classification

Weakness
  • CWE-119 Improper Restriction of Operations within the Bounds of a Memory Buffer
Technology feeds

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.