CVE-2025-6543 CRITICAL

CVE-2025-6543: Memory overflow vulnerability leading to unintended control flow and Denial of Service

Vendor Netscaler
Product ADC
Weakness CWE-119
KEV Status Known Exploited
Published June 25, 2025
Last update February 26, 2026
View on NVD All CVEs

CVSS base score

9.2/10
Attack vector Network
Attack complexity High
Privileges required None
User interaction None
Confidentiality —
Integrity —

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

What the vulnerability does

01Description

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

CISA mandated remediation

02CISA Required Action

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

Key dates

03Disclosure timeline

June 25, 2025 CVE published
February 26, 2026 Record updated