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CVE-2025-6543

Memory overflow vulnerability leading to unintended control flow and Denial of Service

  • Critical 9.2
  • Exploited: added to CISA KEV 30 Jun 2025

Description

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

Key facts

Published
25 Jun 2025
Last changed
26 Feb 2026
Assigned by
Citrix
KEV added
30 Jun 2025
KEV fix due
21 Jul 2025
EPSS
10.433% likely to be exploited in the next 30 days, higher than 95.814% of CVEs (scores for 15 Nov 2026)
SSVC (CISA)
Exploitation: active; Automatable: no; Technical impact: total

Severity scores

Each score is shown as its source gave it. They are not averaged or merged.

  • 9.2CVSS 4.0, Criticalfrom the CNA (Citrix)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

What to do

  • Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.CISA KEV required action

Historical context and remediation

This reference retains the original CVE publication date. A recent record update does not mean a new attack occurred.

No separately sourced impact summary is available on this page yet. Consult the description, version data and dated exploitation evidence.

Version statuses below come from the CNA. An “unaffected” version is not necessarily a currently supported release or proof of a patch date. EPSS is a dated risk estimate, not a count of historical attacks.

Read the original CVE record.

Affected products

VendorProductVersions
NetScalerADC
  • Default status: unaffected
  • 14.1 up to but excluding 47.46 (affected)
  • 13.1 up to but excluding 59.19 (affected)
  • 13.1 FIPS and NDcPP up to but excluding 37.236 (affected)
NetScalerGateway
  • Default status: unaffected
  • 14.1 up to but excluding 47.46 (affected)
  • 13.1 up to but excluding 59.19 (affected)
  • 13.1 FIPS and NDcPP up to but excluding 37.236 (affected)

Timeline

  1. 25 Jun 2025 Published
  2. 30 Jun 2025 CVE-2025-6543 added to CISA KEV
  3. 30 Jun 2025 Added to the CISA KEV catalogue

Weakness

References