---
cve: "CVE-2026-59903"
severity: "MEDIUM"
cvss: 6.5
epss: "40%"
vendor: "netty"
kev: false
exploited: false
published: "2026-08-17 18:17:36"
tags: [cve, security, medium]
source: tsecurity.de CVE-Dossier
exported: "2026-09-10T21:54:08+02:00"
---

# CVE-2026-59903

> 6.5 MEDIUM · 🧪 PoC

## Beschreibung

Netty is an asynchronous, event-driven network application framework. Prior to 4.1.137.Final and 4.2.17.Final, io.netty.handler.codec.http.cors.CorsHandler setVaryHeader replaces application Vary headers such as Authorization or Cookie with Origin, allowing a caching proxy or CDN to reuse authenticated responses across users and disclose sensitive information. This issue is fixed in versions 4.1.137.Final and 4.2.17.Final.

## CVSS-Vektor

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

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

## Patch verfügbar (OSV)

- 5471f0a6ffa4ab39db22c468c6c851af4ecae709 (Commit)
- e0789d32c72f46fd2e7c99b6fdbbf7e2f4409e44 (Commit)

## Referenzen

- <https://github.com/netty/netty/security/advisories/GHSA-8c42-7qj2-3j46>
- <https://github.com/netty/netty/pull/17213>
- <https://github.com/netty/netty/pull/17217>
- <https://github.com/netty/netty/releases/tag/netty-4.1.137.Final>
- <https://github.com/netty/netty/releases/tag/netty-4.2.17.Final>

---
_Exportiert aus dem [tsecurity.de CVE-Dossier](https://tsecurity.de/cve?cve=CVE-2026-59903) · Datenquellen: EUVD (ENISA), NVD, OSV, CISA KEV, FIRST EPSS, Exploit-DB, BSI BITS_