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Weekly Signal
Live intelligence Updated 20 Aug 2026 · 23:29 UTC

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

CVE-2025-6543

Citrix NetScaler ADC and Gateway Buffer Overflow Vulnerability

Recommended action

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

View response plan
CVSS9.2
EPSS10.1%
KEVYes
ExploitationConfirmed exploitation
RemediationExplicit patch identified ↓

Assessment

Why it matters

CISA lists this vulnerability as known to be exploited; exploitation is confirmed; EPSS is 10.1%; technical severity is CVSS 9.2.

Memory overflow vulnerability leading to unintended control flow and Denial of Service in NetScaler ADC and NetScaler Gateway when configured as Gateway (VPN virtual server, ICA Proxy, CVPN, RDP Proxy) OR AAA virtual server

Who should care

  • Teams operating NetScaler ADC and 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 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 patch Article
  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.

Patch

Required Action

Technical details

CVSS vector
CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:L/SI:L/SA:L/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
CWE
CWE-119
Affected versions
Citrix NetScaler ADC and Gateway; Citrix Netscaler Application Delivery Controller (Start Including 13.1, End Excluding 13.1-37.236 | Start Including 13.1, End Excluding 13.1-37.236 | Start Including 13.1, End Excluding 13.1-59.19 | Start Including 14.1, End Excluding 14.1-47.46); Citrix Netscaler Gateway (Start Including 13.1, End Excluding 13.1-59.19 | Start Including 14.1, End Excluding 14.1-47.46)
Fixed versions
Citrix Netscaler Application Delivery Controller (Fixed from 13.1-37.236, 13.1-59.19, 14.1-47.46); Citrix Netscaler Gateway (Fixed from 13.1-59.19, 14.1-47.46)
Published
25 June 2025
Attack vector
Network
Privileges required
None
User interaction
None

Signal timeline

  1. CVE published
  2. Added to CISA KEV
  3. Latest EPSS score: 10.1%
  4. Signal calculated at 71

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.