---
cve: "CVE-2021-39185"
severity: "CRITICAL"
cvss: 9.1
epss: "0.6%"
vendor: "http4s"
kev: false
exploited: false
published: "2021-09-01 20:15:07"
tags: [cve, security, critical]
source: tsecurity.de CVE-Dossier
exported: "2026-09-24T07:11:23+02:00"
---

# CVE-2021-39185

> 9.1 CRITICAL · 🧪 PoC

## Beschreibung

Http4s is a minimal, idiomatic Scala interface for HTTP services. In http4s versions 0.21.26 and prior, 0.22.0 through 0.22.2, 0.23.0, 0.23.1, and 1.0.0-M1 through 1.0.0-M24, the default CORS configuration is vulnerable to an origin reflection attack. The middleware is also susceptible to a Null Origin Attack. The problem is fixed in 0.21.27, 0.22.3, 0.23.2, and 1.0.0-M25. The original `CORS` implementation and `CORSConfig` are deprecated. See the GitHub GHSA for more information, including code examples and workarounds.

## CVSS-Vektor

```
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
```

| Metrik | Wert | Bewertung |
|---|---|---|
| AV Angriffsvektor | Netzwerk | bad |
| AC Komplexität | Gering | bad |
| PR Privilegien | Keine | bad |
| UI Interaktion | Keine | bad |
| S Scope | Unverändert | good |
| C Vertraulichkeit | Hoch | bad |
| I Integrität | Hoch | bad |
| A Verfügbarkeit | Keine | good |

## Patch verfügbar (OSV)

- 5ebfb746ff98817959cbcce3ab2520342253c608 (Commit)

## Referenzen

- <https://github.com/http4s/http4s/security/advisories/GHSA-52cf-226f-rhr6>
- <https://github.com/http4s/http4s/releases/tag/v0.23.2>

---
_Exportiert aus dem [tsecurity.de CVE-Dossier](https://tsecurity.de/cve?cve=CVE-2021-39185) · Datenquellen: EUVD (ENISA), NVD, OSV, CISA KEV, FIRST EPSS, Exploit-DB, BSI BITS_