# CVE-2023-6549: Citrix NetScaler ADC and NetScaler Gateway Buffer Overflow Vulnerability

- Exploited (CISA KEV): yes, added 2024-01-17
- Published: 2024-01-17
- CVSS: 8.2 HIGH (v3.1)
- EPSS: 57.6% (99th percentile)
- CWE: CWE-119

Improper Restriction of Operations within the Bounds of a Memory Buffer in NetScaler ADC and NetScaler Gateway allows Unauthenticated Denial of Service and Out-Of-Bounds Memory Read

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

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

## Our test (measured)

- OWASP Core Rule Set 4.25.0, paranoia level 1, anomaly threshold 5, default CRS settings: passed (0 of 1 requests blocked), template CVE-2023-6549, 2026-11-02
- OWASP Core Rule Set 4.25.0, paranoia level 2, anomaly threshold 5, default CRS settings: passed (0 of 1 requests blocked), template CVE-2023-6549, 2026-11-02

"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-2023-6549 · JSON: https://cve.vigilbase.com/api/v1/cves/CVE-2023-6549