Netty netty-tcnative before 2.0.84.Final SNI Hostname Spoofing via Modified UTF-8 Decoding

{
  "id": "bb19972bec10bd3fcbc72918fd592c75ec235cfc892aee487232fc235b39d620",
  "url": "https://www.cve.org/CVERecord?id=CVE-2026-116542",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "Netty netty-tcnative before 2.0.84.Final SNI Hostname Spoofing via Modified UTF-8 Decoding",
    "summary": "Netty netty-tcnative before 2.0.84.Final contains an SNI hostname spoofing vulnerability that allows remote unauthenticated clients to alter hostnames via JNI NewStringUTF decoding. Attackers can send overlong encodings like 0xC0 0x80 in the ClientHello server_name to confuse SNI-based certificate selection, access decisions, and logging.",
    "evidence": "cve:CVE-2026-116542",
    "products": [
      {
        "name": {
          "value": "netty-tcnative",
          "evidence": "/containers/cna/affected/0/product"
        },
        "prerequisites": [],
        "fixed_versions": [],
        "affected_versions": []
      },
      {
        "name": {
          "value": "netty-tcnative-boringssl-static",
          "evidence": "/containers/cna/affected/1/product"
        },
        "prerequisites": [],
        "fixed_versions": [],
        "affected_versions": []
      }
    ],
    "severity": "medium",
    "structured": {
      "id": "CVE-2026-116542",
      "aliases": [
        "CVE-2026-116542"
      ],
      "metrics": [
        {
          "format": "CVSS",
          "cvssV4_0": {
            "version": "4.0",
            "baseScore": 6.9,
            "attackVector": "NETWORK",
            "baseSeverity": "MEDIUM",
            "vectorString": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N",
            "userInteraction": "NONE",
            "attackComplexity": "LOW",
            "attackRequirements": "NONE",
            "privilegesRequired": "NONE",
            "subIntegrityImpact": "NONE",
            "vulnIntegrityImpact": "LOW",
            "subAvailabilityImpact": "NONE",
            "vulnAvailabilityImpact": "NONE",
            "subConfidentialityImpact": "NONE",
            "vulnConfidentialityImpact": "NONE"
          }
        },
        {
          "format": "CVSS",
          "cvssV3_1": {
            "scope": "UNCHANGED",
            "version": "3.1",
            "baseScore": 5.3,
            "attackVector": "NETWORK",
            "baseSeverity": "MEDIUM",
            "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N",
            "integrityImpact": "LOW",
            "userInteraction": "NONE",
            "attackComplexity": "LOW",
            "availabilityImpact": "NONE",
            "privilegesRequired": "NONE",
            "confidentialityImpact": "NONE"
          }
        }
      ],
      "affected": [
        {
          "repo": "https://github.com/netty/netty-tcnative",
          "vendor": "netty",
          "product": "netty-tcnative",
          "versions": [
            {
              "status": "affected",
              "version": "0",
              "lessThan": "2.0.84.Final",
              "versionType": "custom"
            }
          ],
          "packageURL": "pkg:maven/io.netty/netty-tcnative",
          "packageName": "io.netty:netty-tcnative",
          "collectionURL": "https://repo1.maven.org/maven2/io/netty/netty-tcnative/",
          "defaultStatus": "unaffected"
        },
        {
          "repo": "https://github.com/netty/netty-tcnative",
          "vendor": "netty",
          "product": "netty-tcnative-boringssl-static",
          "versions": [
            {
              "status": "affected",
              "version": "0",
              "lessThan": "2.0.84.Final",
              "versionType": "custom"
            }
          ],
          "packageURL": "pkg:maven/io.netty/netty-tcnative-boringssl-static",
          "packageName": "io.netty:netty-tcnative-boringssl-static",
          "collectionURL": "https://repo1.maven.org/maven2/io/netty/netty-tcnative-boringssl-static/",
          "defaultStatus": "unaffected"
        }
      ],
      "modified": "2026-10-26T14:59:41.528Z",
      "provider": "cve",
      "references": [
        "https://github.com/netty/netty-tcnative/security/advisories/GHSA-2784-hxmm-4hgf",
        "https://github.com/netty/netty-tcnative/commit/a879c85b9776cf478aada3ca69e60b8c0a99ed38",
        "https://github.com/netty/netty-tcnative/blob/netty-tcnative-parent-2.0.83.Final/openssl-dynamic/src/main/c/sslcontext.c#L2608",
        "https://github.com/netty/netty-tcnative/releases/tag/netty-tcnative-parent-2.0.84.Final",
        "https://github.com/netty/netty-tcnative",
        "https://www.vulncheck.com/advisories/netty-netty-tcnative-before-2.0.84-final-sni-hostname-spoofing-via-modified-utf-8-decoding"
      ],
      "provider_metadata": {
        "cna": {
          "orgId": "83251b91-4cc7-4094-a5c7-464a1b83ea10",
          "shortName": "VulnCheck",
          "dateUpdated": "2026-10-26T14:59:41.528Z"
        }
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-116542",
        "evidence": "/cveMetadata/cveId"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/containers/cna/metrics"
  },
  "source_id": "core-cve",
  "document_id": 314039,
  "published_at": "2026-10-26T14:59:41.528+00:00"
}