# CVE-2019-19781: Citrix ADC, Gateway, and SD-WAN WANOP Appliance Code Execution Vulnerability

- Exploited (CISA KEV): yes, added 2021-11-03, known ransomware use
- Published: 2019-12-27
- CVSS: 9.8 CRITICAL (v3.1)
- EPSS: 100.0% (100th percentile)
- CWE: CWE-22

An issue was discovered in Citrix Application Delivery Controller (ADC) and Gateway 10.5, 11.1, 12.0, 12.1, and 13.0. They allow Directory Traversal.

## 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 | Rule published | — | — |
| Google Cloud | Before feed history | — | — |
| Fastly | Before feed history | — | — |
| F5 | Before feed history | — | — |
| Akamai | No public source | — | — |
| OWASP CRS | Before feed history | — | — |

### Microsoft Azure

- undated · listed · rule 99001002
  > Rule 99001002: Critical - 5 · 2 · Attempted Citrix NSC_USER directory traversal CVE-2019-19781
  Source: https://learn.microsoft.com/en-us/azure/web-application-firewall/afds/waf-front-door-drs
- undated · listed · rule 99001002
  > Rule 99001002: Critical - 5 · 2 · Attempted Citrix NSC_USER directory traversal CVE-2019-19781
  Source: https://learn.microsoft.com/en-us/azure/web-application-firewall/ag/application-gateway-crs-rulegroups-rules

## Our test (measured)

- OWASP Core Rule Set 4.25.0, paranoia level 1, anomaly threshold 5, default CRS settings: blocked (1 of 1 requests blocked), template CVE-2019-19781, 2026-11-02
- OWASP Core Rule Set 4.25.0, paranoia level 2, anomaly threshold 5, default CRS settings: blocked (1 of 1 requests blocked), template CVE-2019-19781, 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-2019-19781 · JSON: https://cve.vigilbase.com/api/v1/cves/CVE-2019-19781