Envoy: HTTP/3 connection pool selection null-derefs in ProdClusterManagerFactory::allocateConnPool when transport_socket_options is null

{
  "id": "eb0707f0a633f29da99348e87c85f7eca58f214e057ce4881a2093ba7225716e",
  "url": "https://osv.dev/vulnerability/BIT-envoy-2026-48521",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "Envoy: HTTP/3 connection pool selection null-derefs in ProdClusterManagerFactory::allocateConnPool when transport_socket_options is null",
    "summary": "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.",
    "evidence": "osv:BIT-envoy-2026-48521",
    "products": [
      {
        "name": {
          "value": "envoy",
          "evidence": "/affected/0/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "1.36.10",
            "evidence": "/affected/0/ranges"
          },
          {
            "value": "1.37.6",
            "evidence": "/affected/0/ranges"
          },
          {
            "value": "1.38.4",
            "evidence": "/affected/0/ranges"
          },
          {
            "value": "1.39.1",
            "evidence": "/affected/0/ranges"
          }
        ],
        "affected_versions": []
      }
    ],
    "severity": "medium",
    "structured": {
      "id": "BIT-envoy-2026-48521",
      "aliases": [
        "BIT-envoy-2026-48521",
        "CVE-2026-48521",
        "GHSA-5vff-j9p4-38j3"
      ],
      "affected": [
        {
          "ranges": [
            {
              "type": "SEMVER",
              "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"
                }
              ]
            }
          ],
          "package": {
            "name": "envoy",
            "purl": "pkg:bitnami/envoy",
            "ecosystem": "Bitnami"
          },
          "severity": [
            {
              "type": "CVSS_V3",
              "score": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H"
            }
          ],
          "database_specific": {
            "source": "https://github.com/bitnami/vulndb/tree/main/data/envoy/BIT-envoy-2026-48521.json"
          }
        }
      ],
      "modified": "2026-10-06T15:15:03.818777558Z",
      "provider": "osv",
      "references": [
        "https://github.com/envoyproxy/envoy/commit/8ef2da8527fcd17388b046c1add4fb47fb5d0868",
        "https://github.com/envoyproxy/envoy/commit/cec4899acf03cf551f28611a5f32385648d95f96",
        "https://github.com/envoyproxy/envoy/commit/e7b4839beef7f43594ce8e94c4563c80db04a8a7",
        "https://github.com/envoyproxy/envoy/commit/f5436f44103fb14cb8ba42a8db0f54a06c98c45a",
        "https://github.com/envoyproxy/envoy/releases/tag/v1.36.10",
        "https://github.com/envoyproxy/envoy/releases/tag/v1.37.6",
        "https://github.com/envoyproxy/envoy/releases/tag/v1.38.4",
        "https://github.com/envoyproxy/envoy/releases/tag/v1.39.1",
        "https://github.com/envoyproxy/envoy/security/advisories/GHSA-5vff-j9p4-38j3",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-48521"
      ],
      "provider_metadata": {
        "cpes": [
          "cpe:2.3:a:envoyproxy:envoy:*:*:*:*:*:*:*:*"
        ],
        "severity": "Medium"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-48521",
        "evidence": "/aliases"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/database_specific/severity"
  },
  "source_id": "core-osv",
  "document_id": 89108,
  "published_at": "2026-09-29T08:42:58.854+00:00"
}