# CVE-2019-18678: CVE-2019-18678

- Exploited (CISA KEV): no
- Published: 2019-11-26
- CVSS: not scored
- EPSS: 6.2% (94th percentile)

An issue was discovered in Squid 3.x and 4.x through 4.8. It allows attackers to smuggle HTTP requests through frontend software to a Squid instance that splits the HTTP Request pipeline differently. The resulting Response messages corrupt caches (between a client and Squid) with attacker-controlled content at arbitrary URLs. Effects are isolated to software between the attacker client and Squid. There are no effects on Squid itself, nor on any upstream servers. The issue is related to a request header containing whitespace between a header name and a colon.

## 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 | No public claim | — | — |
| Google Cloud | Before feed history | — | — |
| Fastly | Before feed history | — | — |
| F5 | Rule published | 2023-07-11 | — |
| Akamai | No public source | — | — |
| OWASP CRS | Before feed history | — | — |

### F5

- 2023-07-11 · updated · rule 200018079
  > Updated: signature 200018079 "Trailing Space in Header Name (First Header)" (Other Application Attacks, risk High), systems: System Independent. References: CVE-2019-18678.
  Source: https://docs.cloud.f5.com/docs-v2/platform/changelogs/security-details-changelog
- 2023-08-08 · updated · rule 200018079
  > Updated: signature 200018079 "Trailing Space in Header Name (First Header)" (Other Application Attacks, risk High), systems: System Independent. References: CVE-2019-18678.
  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-2019-18678 · JSON: https://cve.vigilbase.com/api/v1/cves/CVE-2019-18678