{
  "affected": [
    {
      "ranges": [
        {
          "database_specific": {
            "cpe": "cpe:2.3:a:envoyproxy:envoy:*:*:*:*:*:*:*:*",
            "extracted_events": [
              {
                "introduced": "0"
              },
              {
                "fixed": "1.35.13"
              },
              {
                "introduced": "1.36.0"
              },
              {
                "fixed": "1.36.9"
              },
              {
                "introduced": "1.37.0"
              },
              {
                "fixed": "1.37.5"
              },
              {
                "introduced": "1.38.0"
              },
              {
                "fixed": "1.38.3"
              }
            ],
            "source": "CPE_RANGE"
          },
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "adb998f2875986005be294d10231a9c9a497e30d"
            },
            {
              "introduced": "63ee0dc79dce88117c6bd2df5a742f8eb67ea980"
            },
            {
              "fixed": "57198c441a298a75097c690726d90974549a9778"
            },
            {
              "introduced": "6d9bb7d9a85d616b220d1f8fe67b61f82bbdb8d3"
            },
            {
              "fixed": "f97695a50e11f5ff6719e129a466bf9204b64a7f"
            },
            {
              "introduced": "f1dd21b16c244bda00edfb5ffce577e12d0d2ec2"
            },
            {
              "fixed": "0ebfcfe5b0484b89ca85b761da9e05ce75dbda8d"
            }
          ],
          "repo": "https://github.com/envoyproxy/envoy",
          "type": "GIT"
        }
      ]
    }
  ],
  "aliases": [
    "GHSA-f8x4-rw5x-f3r7"
  ],
  "database_specific": {
    "cna_assigner": "GitHub_M",
    "cwe_ids": [
      "CWE-158"
    ],
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/47xxx/CVE-2026-47778.json"
  },
  "details": "Envoy is an open source edge and service proxy designed for cloud-native applications. Prior to 1.35.11, 1.36.7, 1.37.3, and 1.38.1, a structural flaw was identified in DefaultCertValidator::verifySubjectAltName where the extracted DNS SAN string is cast to a C-style string using .c_str() before being passed to the Utility::dnsNameMatch() algorithm. If the attacker serves a certificate with a dNSName SAN containing an embedded NUL byte, the helper Utility::generalNameAsString captures the complete string including the NUL. However, when .c_str() evaluates it, implicit conversion to absl::string_view inside dnsNameMatch relies on strlen(), prematurely truncating the evaluation context. Envoy evaluates trucated string against the exact required config_san match and returns true, thereby successfully validating the string with the Nul byte for an upstream routing. This vulnerability is fixed in 1.35.11, 1.36.7, 1.37.3, and 1.38.1.",
  "id": "CVE-2026-47778",
  "modified": "2026-08-12T03:51:48.549921839Z",
  "published": "2026-06-26T17:27:57.707Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/47xxx/CVE-2026-47778.json"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/envoyproxy/envoy/security/advisories/GHSA-f8x4-rw5x-f3r7"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-47778"
    }
  ],
  "schema_version": "1.9.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:U/C:H/I:N/A:N",
      "type": "CVSS_V3"
    }
  ],
  "summary": "Envoy: Embedded NUL in TLS DNS SAN Truncation in the Default TLS Certificate Validator. (Auth Bypass)"
}