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.
{
"cwe_ids": [
"CWE-297"
],
"cna_assigner": "VulnCheck",
"osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/62xxx/CVE-2026-62243.json"
}{
"source": "AFFECTED_FIELD",
"extracted_events": [
{
"introduced": "4.2.0.Final"
},
{
"fixed": "4.2.16.Final"
},
{
"introduced": "0"
},
{
"fixed": "4.1.137.Final"
}
]
}