ClosedPatched

Citrix NetScaler ADC and Gateway: NetScaler ADC and Gateway Buffer Overflow Vulnerability

Citrix NetScaler ADC and Gateway

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. Added to CISA KEV on 2025-06-30.

Why this severity: CVSS 9.2 (CNA, v4.0); actively exploited (CISA KEV)

Started: Jun 30, 2025
Closed: Jun 30, 2025
CVE: CVE-2025-6543

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Updated Jun 30, 2025

Affected

See vendor advisory / CISA notes (versions not always listed in KEV feed)

Fixed in

See vendor advisory linked in sources

Timeline1

Jun 30, 2025
CISA added CVE-2025-6543 to the KEV catalog (due 2025-07-21).

Advisories4

Notes & caveats

Derived from CISA KEV JSON feed catalogVersion 2026.10.21. CVSS from the CVE record (cvelistV5). Exact affected/fixed version strings are not always in the KEV record; verify against the vendor advisory URL. startedAt uses dateAdded (exploitation may have begun earlier; many entries are older CVEs newly confirmed as exploited in 2025).

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