# CVE-2016-4437: Apache Shiro Code Execution Vulnerability

- Exploited (CISA KEV): yes, added 2021-11-03
- Published: 2016-06-07
- CVSS: 9.8 CRITICAL (v3.1)
- EPSS: 93.0% (100th percentile)
- CWE: CWE-284

Apache Shiro before 1.2.5, when a cipher key has not been configured for the "remember me" feature, allows remote attackers to execute arbitrary code or bypass intended access restrictions via an unspecified request parameter.

## 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 | Rule published | 2023-08-08 | — |
| Akamai | No public source | — | — |
| OWASP CRS | Before feed history | — | — |

### F5

- 2023-08-08 · updated · rule 200104638
  > Updated: signature 200104638 "Apache Shiro rememberMe Cookie Unsafe Deserialization" (Server Side Code Injection, risk High), systems: Java Servlets/JSP. References: CVE-2019-12422, CVE-2016-4437.
  Source: https://docs.cloud.f5.com/docs-v2/platform/changelogs/security-details-changelog
- 2023-09-12 · updated · rule 200104638
  > Updated: signature 200104638 "Apache Shiro rememberMe Cookie Unsafe Deserialization" (Server Side Code Injection, risk High), systems: Java Servlets/JSP. References: CVE-2019-12422, CVE-2016-4437.
  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 1 requests blocked), template CVE-2016-4437, 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-2016-4437, 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-2016-4437 · JSON: https://cve.vigilbase.com/api/v1/cves/CVE-2016-4437