CVE-2026-62243

Summary

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.

Affected Software

VendorProductVersion RangeStatus
nettynetty4.2.0.Final < 4.2.16.Finalaffected
nettynetty4.2.16.Finalunaffected
nettynetty0 < 4.1.137.Finalaffected
nettynetty4.1.137.Finalunaffected

Weaknesses

  • CWE-297: Improper Validation of Certificate with Host Mismatch

References