Netty 4.2.11 through 4.2.17 QUIC Hostname Verification Bypass

{
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "cveMetadata": {
    "cveId": "CVE-2026-100665",
    "assignerOrgId": "83251b91-4cc7-4094-a5c7-464a1b83ea10",
    "assignerShortName": "VulnCheck",
    "dateUpdated": "2026-09-26T13:23:31.242Z",
    "dateReserved": "2026-09-26T02:33:59.039Z",
    "datePublished": "2026-09-26T13:23:31.242Z",
    "state": "PUBLISHED"
  },
  "containers": {
    "cna": {
      "providerMetadata": {
        "orgId": "83251b91-4cc7-4094-a5c7-464a1b83ea10",
        "shortName": "VulnCheck",
        "dateUpdated": "2026-09-26T13:23:31.242Z"
      },
      "datePublic": "2026-09-10T00:00:00.000Z",
      "title": "Netty 4.2.11 through 4.2.17 QUIC Hostname Verification Bypass",
      "descriptions": [
        {
          "lang": "en",
          "value": "Netty versions from 4.2.11.Final before 4.2.18.Final contain an incomplete hostname verification fix in the QUIC certificate verification path when using a plain X509TrustManager. The BoringSSLCertificateVerifyCallback discards the SSLEngine for plain trust managers, preventing endpoint identification from running even when HTTPS verification is configured. Attackers on the network path can present a certificate chain for the wrong hostname that the plain trust manager accepts, bypassing hostname authentication for QUIC clients."
        }
      ],
      "affected": [
        {
          "vendor": "netty",
          "product": "netty",
          "defaultStatus": "unaffected",
          "versions": [
            {
              "version": "4.2.11.Final",
              "status": "affected",
              "versionType": "semver",
              "lessThan": "4.2.18.Final"
            },
            {
              "version": "4.2.18.Final",
              "status": "unaffected",
              "versionType": "semver"
            }
          ]
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "lang": "en",
              "description": "Improper Certificate Validation",
              "cweId": "CWE-295",
              "type": "CWE"
            }
          ]
        }
      ],
      "references": [
        {
          "url": "https://github.com/netty/netty/security/advisories/GHSA-mj35-3qqm-q387",
          "name": "GitHub Security Advisory (GHSA-mj35-3qqm-q387)",
          "tags": [
            "vendor-advisory"
          ]
        },
        {
          "url": "https://github.com/netty/netty/commit/09e72c4fd8007277121ed48db63a124b112b96fe",
          "name": "Patch Commit",
          "tags": [
            "patch"
          ]
        },
        {
          "url": "https://github.com/netty/netty/commit/994e887ed9",
          "name": "Patch Commit",
          "tags": [
            "patch"
          ]
        },
        {
          "url": "https://www.vulncheck.com/advisories/netty-4.2.11-through-4.2.17-quic-hostname-verification-bypass",
          "name": "VulnCheck Advisory: Netty 4.2.11 through 4.2.17 QUIC Hostname Verification Bypass",
          "tags": [
            "third-party-advisory"
          ]
        }
      ],
      "metrics": [
        {
          "format": "CVSS"
        },
        {
          "format": "CVSS",
          "cvssV3_1": {
            "version": "3.1",
            "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N",
            "attackVector": "NETWORK",
            "attackComplexity": "LOW",
            "privilegesRequired": "NONE",
            "userInteraction": "NONE",
            "scope": "UNCHANGED",
            "confidentialityImpact": "HIGH",
            "integrityImpact": "NONE",
            "availabilityImpact": "NONE",
            "baseScore": 7.5,
            "baseSeverity": "HIGH"
          }
        }
      ],
      "credits": [
        {
          "lang": "en",
          "value": "rexpository",
          "type": "reporter"
        }
      ]
    }
  }
}