{
  "affected": [
    {
      "ranges": [
        {
          "database_specific": {
            "extracted_events": [
              {
                "introduced": "0"
              },
              {
                "fixed": "1.36.10"
              },
              {
                "introduced": "1.37.0"
              },
              {
                "fixed": "1.37.6"
              },
              {
                "introduced": "1.38.0"
              },
              {
                "fixed": "1.38.4"
              },
              {
                "introduced": "1.39.0"
              },
              {
                "fixed": "1.39.1"
              }
            ],
            "source": [
              "AFFECTED_FIELD",
              "REFERENCES"
            ]
          },
          "events": [
            {
              "introduced": "0"
            },
            {
              "introduced": "6d9bb7d9a85d616b220d1f8fe67b61f82bbdb8d3"
            },
            {
              "introduced": "f1dd21b16c244bda00edfb5ffce577e12d0d2ec2"
            },
            {
              "introduced": "8eea3285d6bdb89f8ea34632cfe7ce1608a8f374"
            },
            {
              "fixed": "053a8989382dd91542ecf0cef8f379b9cb761cdd"
            },
            {
              "fixed": "cf413bdb37b36d3ffbe570b8a48760abe2b588f5"
            },
            {
              "fixed": "ef2d997c1b022cf8b849a1d3521fbf234d79ca26"
            },
            {
              "fixed": "b579d07d3ad7ee11d32b105e91a5a39ad24718d7"
            },
            {
              "fixed": "8ef2da8527fcd17388b046c1add4fb47fb5d0868"
            },
            {
              "fixed": "cec4899acf03cf551f28611a5f32385648d95f96"
            },
            {
              "fixed": "e7b4839beef7f43594ce8e94c4563c80db04a8a7"
            },
            {
              "fixed": "f5436f44103fb14cb8ba42a8db0f54a06c98c45a"
            }
          ],
          "repo": "https://github.com/envoyproxy/envoy",
          "type": "GIT"
        }
      ]
    }
  ],
  "aliases": [
    "GHSA-5vff-j9p4-38j3"
  ],
  "database_specific": {
    "cna_assigner": "GitHub_M",
    "cwe_ids": [
      "CWE-476"
    ],
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/48xxx/CVE-2026-48521.json"
  },
  "details": "Envoy is an open source edge and service proxy designed for cloud-native applications. Prior to 1.36.10, 1.37.6, 1.38.4, and 1.39.1, Envoy's ProdClusterManagerFactory::allocateConnPool dereferences transport_socket_options while selecting an HTTP/3 connection pool without first checking whether the pointer is null. LoadBalancerContext implementations used by synthetic, mirror, health-check, and async-client calls can return no transport-socket options. With auto_config and HTTP/3 enabled, routine traffic reaching one of those contexts can crash an Envoy worker. The relevant scope boundary is that the affected branch requires HTTP/3 in the protocol set and a context that supplies no transport-socket options. This issue is fixed in versions 1.36.10, 1.37.6, 1.38.4, and 1.39.1.",
  "id": "CVE-2026-48521",
  "modified": "2026-09-25T03:30:51.081957735Z",
  "published": "2026-09-21T19:44:15.389Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/envoyproxy/envoy/releases/tag/v1.36.10"
    },
    {
      "type": "WEB",
      "url": "https://github.com/envoyproxy/envoy/releases/tag/v1.37.6"
    },
    {
      "type": "WEB",
      "url": "https://github.com/envoyproxy/envoy/releases/tag/v1.38.4"
    },
    {
      "type": "WEB",
      "url": "https://github.com/envoyproxy/envoy/releases/tag/v1.39.1"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/48xxx/CVE-2026-48521.json"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/envoyproxy/envoy/security/advisories/GHSA-5vff-j9p4-38j3"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-48521"
    },
    {
      "type": "FIX",
      "url": "https://github.com/envoyproxy/envoy/commit/8ef2da8527fcd17388b046c1add4fb47fb5d0868"
    },
    {
      "type": "FIX",
      "url": "https://github.com/envoyproxy/envoy/commit/cec4899acf03cf551f28611a5f32385648d95f96"
    },
    {
      "type": "FIX",
      "url": "https://github.com/envoyproxy/envoy/commit/e7b4839beef7f43594ce8e94c4563c80db04a8a7"
    },
    {
      "type": "FIX",
      "url": "https://github.com/envoyproxy/envoy/commit/f5436f44103fb14cb8ba42a8db0f54a06c98c45a"
    }
  ],
  "schema_version": "1.9.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H",
      "type": "CVSS_V3"
    }
  ],
  "summary": "Envoy: HTTP/3 connection pool selection null-derefs in ProdClusterManagerFactory::allocateConnPool when transport_socket_options is null"
}