{
  "affected": [
    {
      "ranges": [
        {
          "database_specific": {
            "extracted_events": [
              {
                "introduced": "4.2.0.Final"
              },
              {
                "fixed": "4.2.16.Final"
              },
              {
                "introduced": "0"
              },
              {
                "fixed": "4.1.137.Final"
              }
            ],
            "source": "AFFECTED_FIELD"
          },
          "events": [
            {
              "introduced": "09e64d259c99be8b5b2a471a78f11e65eb82598a"
            },
            {
              "fixed": "3703d79669ee024f6483c9d8697ac58ba546df33"
            },
            {
              "introduced": "0"
            },
            {
              "fixed": "5471f0a6ffa4ab39db22c468c6c851af4ecae709"
            }
          ],
          "repo": "https://github.com/netty/netty",
          "type": "GIT"
        }
      ]
    }
  ],
  "aliases": [
    "GHSA-p85m-gvr3-788c"
  ],
  "database_specific": {
    "cna_assigner": "VulnCheck",
    "cwe_ids": [
      "CWE-297"
    ],
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/62xxx/CVE-2026-62243.json"
  },
  "details": "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.",
  "id": "CVE-2026-62243",
  "modified": "2026-08-25T03:51:43.198817294Z",
  "published": "2026-08-22T12:26:43.072Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/62xxx/CVE-2026-62243.json"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/netty/netty/security/advisories/GHSA-p85m-gvr3-788c"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-62243"
    },
    {
      "type": "ADVISORY",
      "url": "https://www.vulncheck.com/advisories/netty-through-tls-hostname-verification-bypass"
    }
  ],
  "schema_version": "1.9.0",
  "severity": [
    {
      "score": "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",
      "type": "CVSS_V4"
    }
  ],
  "summary": "Netty 4.2.0 through 4.2.16 TLS Hostname Verification Bypass"
}