CVE-2025-6543 — Citrix NetScaler ADC and Gateway Buffer Overflow Vulnerability

CISA KEV listed Added June 30, 2025 Remediate by July 21, 2025

Description

Citrix NetScaler ADC and Gateway contain a buffer overflow vulnerability leading to unintended control flow and Denial of Service. NetScaler must be configured as Gateway (VPN virtual server, ICA Proxy, CVPN, RDP Proxy) OR AAA virtual server.

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.

Notes

https://support.citrix.com/support-home/kbsearch/article?articleNumber=CTX694788 ; https://www.netscaler.com/blog/news/netscaler-critical-security-updates-for-cve-2025-6543-and-cve-2025-5777/ ; https://nvd.nist.gov/vuln/detail/CVE-2025-6543

Need help remediating this vulnerability?

Our team helps organizations patch, mitigate, and respond to CISA KEV advisories fast.

Talk to an engineer