CVE-2026-62243: Netty

High severity, CVSS 7.5. EPSS: 0.2% chance of exploitation in the next 30 days.

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 products

• Netty Netty: from 4.2.0.Final, before 4.2.16.Final (fixed in 4.2.16.Final); before 4.1.137.Final (fixed in 4.1.137.Final)

Published 2026-08-22. Last modified 2026-09-10.