# CVE-2017-9791: Apache Struts 1 Improper Input Validation Vulnerability

- Exploited (CISA KEV): yes, added 2022-02-10
- Published: 2017-07-10
- CVSS: 9.8 CRITICAL (v3.1)
- EPSS: 98.9% (100th percentile)
- CWE: CWE-20

The Struts 1 plugin in Apache Struts 2.1.x and 2.3.x might allow remote code execution via a malicious field value passed in a raw message to the ActionMessage.

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

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

## 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-2017-9791, 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-2017-9791, 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.

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