Envoy: ext_authz Use-After-Free during Stream Teardown with Per-Route Overrides

{
  "id": "6e758b1ee84b09ed5dc9c4c55a1485f9c55d69d7fa0b61a27a883d6dd4cbd159",
  "url": "https://osv.dev/vulnerability/CVE-2026-47205",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "Envoy: ext_authz Use-After-Free during Stream Teardown with Per-Route Overrides",
    "summary": "Envoy is an open source edge and service proxy designed for cloud-native applications. From 1.36.0 until 1.36.9, 1.37.5, and 1.38.3, a Use-After-Free (UAF) vulnerability leading to a sudden segmentation fault exists in Envoy's ext_authz HTTP filter when processing per-route authorization overrides concurrently with rapid downstream client disconnects. During standard request lifecycles, Envoy instantiates the ext_authz filter with a foundational authorization client object (client_). If a matched route dictates a dynamic per-route HTTP or gRPC authorization service override, the filter generates a localized client. In the vulnerable implementation, this transient client aggressively overwrote the default client_ unique pointer by executing client_ = std::move(per_route_client). When a client rapidly establishes and subsequently tears down a stream (such as rapidly refreshing a protected WebSocket endpoint), the downstream triggers the ConnectionManagerImpl::doDeferredStreamDestroy() -> ActiveStream::onResetStream() lifecycle. Envoy immediately sequences Filter::onDestroy() in an attempt to securely abort dispatched asynchronous authorization check transactions via client_->cancel(). By destructing the default client abruptly during initiateCall, a memory lifecycle misalignment occurs within the async client manager. The stream teardown fails to reliably track and cancel the dynamically bound asynchronous authorization tasks, orchestrating a sequence where a late asynchronous ",
    "evidence": "osv:CVE-2026-47205",
    "products": [],
    "severity": "medium",
    "structured": {
      "id": "CVE-2026-47205",
      "aliases": [
        "BIT-envoy-2026-47205",
        "CVE-2026-47205",
        "GHSA-mvh9-767w-x47j"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://github.com/envoyproxy/envoy",
              "type": "GIT",
              "events": [
                {
                  "introduced": "63ee0dc79dce88117c6bd2df5a742f8eb67ea980"
                },
                {
                  "fixed": "57198c441a298a75097c690726d90974549a9778"
                },
                {
                  "introduced": "6d9bb7d9a85d616b220d1f8fe67b61f82bbdb8d3"
                },
                {
                  "fixed": "f97695a50e11f5ff6719e129a466bf9204b64a7f"
                },
                {
                  "introduced": "f1dd21b16c244bda00edfb5ffce577e12d0d2ec2"
                },
                {
                  "fixed": "0ebfcfe5b0484b89ca85b761da9e05ce75dbda8d"
                }
              ],
              "database_specific": {
                "extracted_events": [
                  {
                    "cpe": "cpe:2.3:a:envoyproxy:envoy:*:*:*:*:*:*:*:*",
                    "range": [
                      {
                        "introduced": "1.36.0"
                      },
                      {
                        "fixed": "1.36.9"
                      }
                    ],
                    "source": "CPE_RANGE"
                  },
                  {
                    "cpe": "cpe:2.3:a:envoyproxy:envoy:*:*:*:*:*:*:*:*",
                    "range": [
                      {
                        "introduced": "1.37.0"
                      },
                      {
                        "fixed": "1.37.5"
                      }
                    ],
                    "source": "CPE_RANGE"
                  },
                  {
                    "cpe": "cpe:2.3:a:envoyproxy:envoy:*:*:*:*:*:*:*:*",
                    "range": [
                      {
                        "introduced": "1.38.0"
                      },
                      {
                        "fixed": "1.38.3"
                      }
                    ],
                    "source": "CPE_RANGE"
                  }
                ]
              }
            }
          ],
          "versions": [
            "v1.38.2",
            "v1.37.4",
            "v1.36.8",
            "v1.38.1",
            "v1.37.3",
            "v1.36.7",
            "v1.38.0",
            "v1.37.2",
            "v1.36.6",
            "v1.37.1",
            "v1.36.5",
            "v1.37.0",
            "v1.36.4",
            "v1.36.3",
            "v1.36.2",
            "v1.36.1",
            "v1.36.0"
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-47205.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:23.288204429Z",
      "provider": "osv",
      "references": [
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/47xxx/CVE-2026-47205.json",
        "https://github.com/envoyproxy/envoy/security/advisories/GHSA-mvh9-767w-x47j",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-47205"
      ],
      "provider_metadata": {
        "cwe_ids": [
          "CWE-416"
        ],
        "cna_assigner": "GitHub_M",
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/47xxx/CVE-2026-47205.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-47205",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 489766,
  "published_at": "2026-06-26T18:01:07.766+00:00"
}