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

- Exploited (CISA KEV): yes, added 2025-06-30
- Published: 2025-06-25
- CVSS: 9.2 CRITICAL (v4.0)
- EPSS: 10.4% (96th percentile)
- CWE: CWE-119

Memory overflow vulnerability leading to unintended control flow and Denial of Service in NetScaler ADC and NetScaler Gateway when configured as Gateway (VPN virtual server, ICA Proxy, CVPN, RDP Proxy) OR AAA virtual server

## Edge WAF coverage (claimed by vendors, not measured)

| Vendor | Status | First rule | Days after publication |
|---|---|---|---|
| Cloudflare | No public claim | — | — |
| AWS | No public claim | — | — |
| Microsoft Azure | No public claim | — | — |
| Google Cloud | No public claim | — | — |
| Fastly | Before feed history | — | — |
| F5 | No public claim | — | — |
| Akamai | No public source | — | — |
| OWASP CRS | No public claim | — | — |

"No public claim" means no vendor statement names this CVE; "Before feed history" means the CVE is older than the vendor feed. In both cases generic rules may still block it.

HTML: https://cve.vigilbase.com/cve/CVE-2025-6543 · JSON: https://cve.vigilbase.com/api/v1/cves/CVE-2025-6543