---
cve: "CVE-2026-62243"
severity: "HIGH"
cvss: 8.7
epss: "0.2%"
vendor: "netty"
kev: false
exploited: false
published: "2026-08-22 13:16:39"
tags: [cve, security, high]
source: tsecurity.de CVE-Dossier
exported: "2026-09-21T06:06:14+02:00"
---

# CVE-2026-62243

> 8.7 HIGH · 🧪 PoC

## Beschreibung

Netty (io.netty:netty-handler) versions from 4.2.0.Final through 4.2.16.Final and versions through 4.1.136.Final disable TLS hostname verification on the SslProvider.OPENSSL client path when a plain (non-extended) X509TrustManager is used and Unsafe-based trust-manager wrapping is unavailable (Java 25+). In this configuration the OpenSSL client does not perform hostname verification, allowing a man-in-the-middle attacker to present a certificate issued for a different hostname that is accepted without validation. Fixed in 4.2.17.Final and 4.1.137.Final.

## CVSS-Vektor

```
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:N/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)

- 3703d79669ee024f6483c9d8697ac58ba546df33 (Commit)
- 5471f0a6ffa4ab39db22c468c6c851af4ecae709 (Commit)

## Referenzen

- <https://github.com/netty/netty/security/advisories/GHSA-p85m-gvr3-788c>
- <https://www.vulncheck.com/advisories/netty-through-tls-hostname-verification-bypass>

---
_Exportiert aus dem [tsecurity.de CVE-Dossier](https://tsecurity.de/cve?cve=CVE-2026-62243) · Datenquellen: EUVD (ENISA), NVD, OSV, CISA KEV, FIRST EPSS, Exploit-DB, BSI BITS_