---
cve: "CVE-2026-59900"
severity: "MEDIUM"
cvss: 6.9
epss: "23%"
vendor: "netty"
kev: false
exploited: false
published: "2026-07-29 18:16:56"
tags: [cve, security, medium]
source: tsecurity.de CVE-Dossier
exported: "2026-09-05T22:47:06+02:00"
---

# CVE-2026-59900

> 6.9 MEDIUM · 🧪 PoC

## Beschreibung

Netty is an asynchronous, event-driven network application framework. Prior to versions 4.1.136.Final and 4.2.16.Final, Netty's HTTP/2-to-HTTP/1.x translation layer (`Http2StreamFrameToHttpObjectCodec` and `InboundHttp2ToHttpAdapter`) fails to deduplicate or validate `Host` headers when an HTTP/2 client supplies both the `:authority` pseudo-header and a literal `host` header in a single HEADERS frame. The translator maps `:authority` to `Host` and separately copies the literal `host` header, producing an `HttpRequest` object containing two `Host` headers with attacker-controlled differing values. This issue has been fixed in versions 4.1.136.Final and 4.2.16.Final.

## CVSS-Vektor

```
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N
```

| Metrik | Wert | Bewertung |
|---|---|---|
| AV Angriffsvektor | Netzwerk | bad |
| AC Komplexität | Gering | bad |
| PR Privilegien | Keine | bad |
| UI Interaktion | Keine | bad |

## Patch verfügbar (OSV)

- fca0764703b3bb59c6e6dc5d29c6d9710d35c0e6 (Commit)
- 3703d79669ee024f6483c9d8697ac58ba546df33 (Commit)

## Referenzen

- <https://github.com/netty/netty/security/advisories/GHSA-c69g-56f8-xwqj>
- <https://github.com/netty/netty/releases/tag/netty-4.1.136.Final>
- <https://github.com/netty/netty/releases/tag/netty-4.2.16.Final>

---
_Exportiert aus dem [tsecurity.de CVE-Dossier](https://tsecurity.de/cve?cve=CVE-2026-59900) · Datenquellen: EUVD (ENISA), NVD, OSV, CISA KEV, FIRST EPSS, Exploit-DB, BSI BITS_