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Weekly Signal
Live intelligence Updated 20 Aug 2026 · 12:21 UTC

Citrix · NetScaler ADC and NetScaler Gateway, Netscaler Application Delivery Controller, Netscaler Gateway

CVE-2023-6549

Citrix NetScaler ADC and NetScaler Gateway Buffer Overflow Vulnerability

Recommended action

Validate affected assets and exposure now, then remediate on an accelerated schedule. Citrix Security advisory

View response plan
CVSS7.5
EPSS57.6%
KEVYes
ExploitationConfirmed exploitation
RemediationNot yet verified ↓

Assessment

Why it matters

CISA lists this vulnerability as known to be exploited; exploitation is confirmed; EPSS is 57.6%; technical severity is CVSS 7.5.

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

Who should care

  • Teams operating NetScaler ADC and NetScaler Gateway, Netscaler Application Delivery Controller, Netscaler Gateway
  • Vulnerability and exposure management teams
  • Security operations teams monitoring exploitation activity

Response plan

What I would do

  1. Confirm whether NetScaler ADC and NetScaler Gateway, Netscaler Application Delivery Controller, Netscaler Gateway is present in the environment.
  2. Identify affected versions and establish whether vulnerable services are exposed or reachable.
  3. Citrix Security advisory
  4. Review relevant security telemetry for evidence of attempted or successful exploitation.
  5. Document the remediation decision and track it to verified completion.

Treatment intelligence

Remediation intelligence

Not yet verified

Vendor sources are listed before government and third-party guidance. Confirm product applicability and change prerequisites before deployment.

Verification noteAutomated link verification has not completed for this guidance yet.

Advisory

Required Action

Technical details

CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
CWE
CWE-119
Affected versions
Citrix NetScaler ADC and NetScaler Gateway; Citrix Netscaler Application Delivery Controller (Start Including 12.1, End Excluding 12.1-55.302 | Start Including 12.1, End Excluding 12.1-55.302 | Start Including 13.0, End Excluding 13.0-92.21 | Start Including 13.1, End Excluding 13.1-37.176); Citrix Netscaler Gateway (Start Including 13.0, End Excluding 13.0-92.21 | Start Including 13.1, End Excluding 13.1-51.15 | Start Including 14.1, End Excluding 14.1-12.35)
Fixed versions
Citrix Netscaler Application Delivery Controller (Fixed from 12.1-55.302, 13.0-92.21, 13.1-37.176, 13.1-51.15, 14.1-12.35); Citrix Netscaler Gateway (Fixed from 13.0-92.21, 13.1-51.15, 14.1-12.35)
Published
17 January 2024
Attack vector
Network
Privileges required
None
User interaction
None

Signal timeline

  1. CVE published
  2. Added to CISA KEV
  3. Latest EPSS score: 57.6%
  4. Signal calculated at 78

External references

Live public intelligence This assessment combines public-source evidence. Validate the affected product, version and exposure against your own environment before making a risk decision.