---
cve: "CVE-2026-89044"
severity: "MEDIUM"
cvss: 6.9
epss: "0.2%"
vendor: "netty"
kev: false
exploited: false
published: "2026-09-10 18:18:16"
tags: [cve, security, medium]
source: tsecurity.de CVE-Dossier
exported: "2026-09-21T15:25:53+02:00"
---

# CVE-2026-89044

> 6.9 MEDIUM · 🧪 PoC

## Beschreibung

Netty versions 4.1.133.Final through 4.1.137.Final and 4.2.13.Final through 4.2.17.Final fail to properly validate the final transfer coding in the Transfer-Encoding header, allowing attackers to smuggle requests by using malformed encoding declarations. Attackers can split Transfer-Encoding headers across multiple lines or use values like 'chunked, xchunked' to bypass validation and decode messages as chunked when the final coding is not chunked, enabling request smuggling attacks.

## CVSS-Vektor

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

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

## Patch verfügbar (OSV)

- 26e68a2c3935e459b374891c87760f6d6c5e2550 (Commit)
- 2521f494432e27415a567d3a81a9eb907abf20b3 (Commit)

## Referenzen

- <https://github.com/netty/netty/security/advisories/GHSA-hcvj-94mj-jp5c>
- <https://github.com/netty/netty/commit/ca87393b0e9e13c493d213a268e727a6d44e1585>
- <https://github.com/netty/netty/commit/640d4d3324f7b811a4903d0730c8ccb35500500c>
- <https://github.com/netty/netty/blob/netty-4.1.137.Final/codec-http/src/main/java/io/netty/handler/codec/http/HttpObjectDecoder.java#L866>
- <https://github.com/netty/netty/releases/tag/netty-4.1.138.Final>
- <https://github.com/netty/netty/releases/tag/netty-4.2.18.Final>
- <https://github.com/netty/netty>
- <https://www.vulncheck.com/advisories/netty-4.1.133-final-through-4.1.137-final-and-4.2.13-final-through-4.2.17-final-http-request-smuggling-via-transfer-encoding>

---
_Exportiert aus dem [tsecurity.de CVE-Dossier](https://tsecurity.de/cve?cve=CVE-2026-89044) · Datenquellen: EUVD (ENISA), NVD, OSV, CISA KEV, FIRST EPSS, Exploit-DB, BSI BITS_