CVE-2026-62243Netty 4.2.0 through 4.2.16 TLS Hostname Verification Bypass

Description

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.

Data: CVE.org, NVD, CISA KEV, FIRST EPSS, Ubuntu. Published as the sources state it, in English.

Affected products and versions

References and patches

• GitHub Security Advisory (GHSA-p85m-gvr3-788c) vendor-advisory
• VulnCheck Advisory: Netty 4.2.0 through 4.2.16 TLS Hostname Verification Bypass third-party-advisory