# CVE-2025-21418: Microsoft Windows Ancillary Function Driver for WinSock Heap-Based Buffer Overflow Vulnerability

- Exploited (CISA KEV): yes, added 2025-02-11
- Published: 2025-02-11
- CVSS: 7.8 HIGH (v3.1)
- EPSS: 2.1% (82th percentile)
- CWE: CWE-122

Windows Ancillary Function Driver for WinSock Elevation of Privilege Vulnerability

## 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-2025-21418 · JSON: https://cve.vigilbase.com/api/v1/cves/CVE-2025-21418