CVE-2025-6543 — Citrix NetScaler ADC and Gateway Buffer Overflow Vulnerability
Overview
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.
Vulnerability details
- CVE ID
- CVE-2025-6543
- Vulnerability
- Citrix NetScaler ADC and Gateway Buffer Overflow Vulnerability
- Vendor
- Citrix
- Affected products
- Citrix: NetScaler ADC and Gateway
- Severity
- HIGH
- Exploitation status
- Actively exploited in the wild (CISA KEV)
- Published
- 2025-06-30
Remediation guidance
CVE-2025-6543 is in CISA's Known Exploited Vulnerabilities (KEV) catalog — U.S. federal civilian agencies are required to remediate it under Binding Operational Directive 22-01. Treat it as a priority for every environment.
Apply the vendor's official security update for Citrix the affected product as soon as possible. Where a patch is unavailable, apply vendor mitigations or isolate/segment exposed systems.
Hunt for indicators of compromise tied to this vulnerability and confirm logging/EDR coverage on affected assets.
Authoritative references
Remediate CVE-2025-6543 — and stay ahead of the next one
CVE-2025-6543 is listed in the CISA KEV catalog as actively exploited — treat remediation as urgent. Scan your domain free to see whether CVE-2025-6543 and other Citrix issues affect you and get a prioritized remediation report (full report from ₹999) — or stream the full feed of 1,600+ actively-exploited CVEs straight into your SOC.
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