Home / Vulnerabilities / CVE-2025-6543
CRITICAL SEVERITY
CVE-2025-6543 Citrix · NetScaler ADC and Gateway

Citrix NetScaler ADC and Gateway Buffer Overflow Vulnerability

Technical Severity

CVSS v3.1 Metrics

CRITICAL
9.8 / 10
Minimal Risk Critical
Vector Specification
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Exploitation Likelihood

EPSS Prediction

3.05 %
Predictive Probability
Percentile Rank
86.4 th

Documented as more likely to be exploited than 86.4% of known CVEs.

Detection Date

Jun 30, 2025

Remediation Due

Jul 21, 2025

CISA Catalog Active

Threat Analysis

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.

Remediation Directive

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

External Intelligence

https://support.citrix.com/support-home/kbsearch/article?articleNumber=CTX694788

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://www.netscaler.com/blog/news/netscaler-critical-security-updates-for-cve-2025-6543-and-cve-2025-5777/
NVD

National Vulnerability Database

https://nvd.nist.gov/vuln/detail/CVE-2025-6543