# CVE-2026-3055: Citrix NetScaler Out-of-Bounds Read Vulnerability

- Exploited (CISA KEV): yes, added 2026-03-30
- Published: 2026-03-23
- CVSS: 9.3 CRITICAL (v4.0)
- EPSS: 91.5% (100th percentile)
- CWE: CWE-125

Insufficient input validation in NetScaler ADC and NetScaler Gateway when configured as a SAML IDP leading to memory overread

## 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 | Rule published | 2026-07-07 | 106 |
| Akamai | No public source | — | — |
| OWASP CRS | No public claim | — | — |

### F5

- 2026-07-07 · new · rule 200009361
  > Added: signature 200009361 "Citrix NetScaler Information Disclosure (2)" (Information Leakage, risk Medium), systems: Citrix. References: CVE-2026-3055.
  Source: https://docs.cloud.f5.com/docs-v2/platform/changelogs/security-details-changelog

## Our test (measured)

- OWASP Core Rule Set 4.25.0, paranoia level 1, anomaly threshold 5, default CRS settings: passed (0 of 2 requests blocked), template CVE-2026-3055, 2026-11-02
- OWASP Core Rule Set 4.25.0, paranoia level 2, anomaly threshold 5, default CRS settings: passed (0 of 2 requests blocked), template CVE-2026-3055, 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-2026-3055 · JSON: https://cve.vigilbase.com/api/v1/cves/CVE-2026-3055