# CVE-2017-9788: Apache Software Foundation Apache HTTP Server

- Exploited (CISA KEV): no
- Published: 2017-07-13
- CVSS: not scored
- EPSS: 56.8% (99th percentile)

In Apache httpd before 2.2.34 and 2.4.x before 2.4.27, the value placeholder in [Proxy-]Authorization headers of type 'Digest' was not initialized or reset before or between successive key=value assignments by mod_auth_digest. Providing an initial key with no '=' assignment could reflect the stale value of uninitialized pool memory used by the prior request, leading to leakage of potentially confidential information, and a segfault in other cases resulting in denial of service.

## 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 | 2026-09-16 | — |
| Akamai | No public source | — | — |
| OWASP CRS | Before feed history | — | — |

### F5

- 2026-09-16 · updated · rule 200012027
  > Updated: signature 200012027 "Digest authentication uninitialized memory reflection" (Denial of Service, risk High), systems: Apache, JBoss. References: CVE-2017-9788.
  Source: https://docs.cloud.f5.com/docs-v2/platform/changelogs/security-details-changelog

"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-2017-9788 · JSON: https://cve.vigilbase.com/api/v1/cves/CVE-2017-9788