{"id":"CVE-2026-62243","state":"PUBLISHED","title":"Netty 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.","publishedAt":"2026-08-22T12:26:43.072Z","updatedAt":"2026-08-24T19:36:53.644Z","severity":{"score":8.7,"label":"High","version":"4.0","vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N","source":"VulnCheck"},"assigner":"VulnCheck","products":["netty netty"],"affected":[{"vendor":"netty","product":"netty","packageURL":"pkg:maven/io.netty/netty-handler","defaultStatus":"unaffected","versions":[{"version":"4.2.0.Final","status":"affected","lessThan":"4.2.16.Final","versionType":"custom"},{"version":"4.2.16.Final","status":"unaffected","versionType":"custom"}]},{"vendor":"netty","product":"netty","packageURL":"pkg:maven/io.netty/netty-handler","defaultStatus":"unaffected","versions":[{"version":"0","status":"affected","lessThan":"4.1.137.Final","versionType":"custom"},{"version":"4.1.137.Final","status":"unaffected","versionType":"custom"}]}],"references":["https://github.com/netty/netty/security/advisories/GHSA-p85m-gvr3-788c","https://www.vulncheck.com/advisories/netty-through-tls-hostname-verification-bypass"],"weaknesses":["CWE-297"],"ingestedAt":"2026-10-29T20:12:32.778Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/62xxx/CVE-2026-62243.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-62243","state":"PUBLISHED","datePublished":"2026-08-22T12:26:43.072Z","dateUpdated":"2026-08-24T19:36:53.644Z","assignerShortName":"VulnCheck","assignerOrgId":"83251b91-4cc7-4094-a5c7-464a1b83ea10","dateReserved":"2026-07-13T16:41:09.007Z"},"containers":{"cna":{"title":"Netty 4.2.0 through 4.2.16 TLS Hostname Verification Bypass","descriptions":[{"lang":"en","value":"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+). 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