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

Vulnerability Name

Citrix NetScaler ADC and Gateway Buffer Overflow Vulnerability

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.

Known To Be Used in Ransomware Campaigns?

Unknown

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.

Additional 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

Related News Articles

Over 3,000 NetScaler devices left unpatched against CitrixBleed 2 bugAugust 12, 2025

Dutch NCSC Confirms Active Exploitation of Citrix NetScaler CVE-2025-6543 in Critical SectorsAugust 12, 2025

Netherlands: Citrix Netscaler flaw CVE-2025-6543 exploited to breach orgsAugust 12, 2025

CISA Adds Citrix NetScaler CVE-2025-5777 to KEV Catalog as Active Exploits Target EnterprisesJuly 11, 2025

CISA Adds Four Critical Vulnerabilities to KEV Catalog Due to Active ExploitationJuly 8, 2025