Is CVE-2026-62243 being exploited?

No public exploit is currently tracked.

How severe is CVE-2026-62243?

CVE-2026-62243 has a CVSS v3 severity of HIGH (7.5).

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CVE-2026-62243

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.