{
    "dataType": "CVE_RECORD",
    "dataVersion": "5.2",
    "cveMetadata": {
        "cveId": "CVE-2026-73548",
        "assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
        "state": "PUBLISHED",
        "assignerShortName": "GitHub_M",
        "dateReserved": "2026-08-12T20:53:46.379Z",
        "datePublished": "2026-09-21T19:35:15.275Z",
        "dateUpdated": "2026-09-24T22:35:14.446Z"
    },
    "containers": {
        "cna": {
            "title": "Envoy: Cross-user response poisoning via a generic (non-WebSocket) HTTP upgrade on Envoy's shared backend pool",
            "problemTypes": [
                {
                    "descriptions": [
                        {
                            "cweId": "CWE-444",
                            "lang": "en",
                            "description": "CWE-444: Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling')",
                            "type": "CWE"
                        }
                    ]
                }
            ],
            "metrics": [
                {
                    "cvssV3_1": {
                        "attackComplexity": "LOW",
                        "attackVector": "NETWORK",
                        "availabilityImpact": "NONE",
                        "baseScore": 7.5,
                        "baseSeverity": "HIGH",
                        "confidentialityImpact": "HIGH",
                        "integrityImpact": "NONE",
                        "privilegesRequired": "NONE",
                        "scope": "UNCHANGED",
                        "userInteraction": "NONE",
                        "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N",
                        "version": "3.1"
                    }
                }
            ],
            "references": [
                {
                    "name": "https://github.com/envoyproxy/envoy/security/advisories/GHSA-3vhp-c83q-jqc2",
                    "tags": [
                        "x_refsource_CONFIRM"
                    ],
                    "url": "https://github.com/envoyproxy/envoy/security/advisories/GHSA-3vhp-c83q-jqc2"
                },
                {
                    "name": "https://github.com/envoyproxy/envoy/commit/309855626966cff176155c821043ed3b44671361",
                    "tags": [
                        "x_refsource_MISC"
                    ],
                    "url": "https://github.com/envoyproxy/envoy/commit/309855626966cff176155c821043ed3b44671361"
                },
                {
                    "name": "https://github.com/envoyproxy/envoy/commit/3c7998545a9c9fb3933a4bc1907d92f0e752bc2b",
                    "tags": [
                        "x_refsource_MISC"
                    ],
                    "url": "https://github.com/envoyproxy/envoy/commit/3c7998545a9c9fb3933a4bc1907d92f0e752bc2b"
                },
                {
                    "name": "https://github.com/envoyproxy/envoy/commit/4633b8cce3d15b8734eefe232e30c12b0140b91c",
                    "tags": [
                        "x_refsource_MISC"
                    ],
                    "url": "https://github.com/envoyproxy/envoy/commit/4633b8cce3d15b8734eefe232e30c12b0140b91c"
                },
                {
                    "name": "https://github.com/envoyproxy/envoy/commit/bd6711f2617658e28dfa3df3dace6bfe3cfc0766",
                    "tags": [
                        "x_refsource_MISC"
                    ],
                    "url": "https://github.com/envoyproxy/envoy/commit/bd6711f2617658e28dfa3df3dace6bfe3cfc0766"
                },
                {
                    "name": "https://github.com/envoyproxy/envoy/releases/tag/v1.36.10",
                    "tags": [
                        "x_refsource_MISC"
                    ],
                    "url": "https://github.com/envoyproxy/envoy/releases/tag/v1.36.10"
                },
                {
                    "name": "https://github.com/envoyproxy/envoy/releases/tag/v1.37.6",
                    "tags": [
                        "x_refsource_MISC"
                    ],
                    "url": "https://github.com/envoyproxy/envoy/releases/tag/v1.37.6"
                },
                {
                    "name": "https://github.com/envoyproxy/envoy/releases/tag/v1.38.4",
                    "tags": [
                        "x_refsource_MISC"
                    ],
                    "url": "https://github.com/envoyproxy/envoy/releases/tag/v1.38.4"
                },
                {
                    "name": "https://github.com/envoyproxy/envoy/releases/tag/v1.39.1",
                    "tags": [
                        "x_refsource_MISC"
                    ],
                    "url": "https://github.com/envoyproxy/envoy/releases/tag/v1.39.1"
                }
            ],
            "affected": [
                {
                    "vendor": "envoyproxy",
                    "product": "envoy",
                    "versions": [
                        {
                            "version": "< 1.36.10",
                            "status": "affected"
                        },
                        {
                            "version": ">= 1.37.0, < 1.37.6",
                            "status": "affected"
                        },
                        {
                            "version": ">= 1.38.0, < 1.38.4",
                            "status": "affected"
                        },
                        {
                            "version": ">= 1.39.0, < 1.39.1",
                            "status": "affected"
                        }
                    ]
                }
            ],
            "providerMetadata": {
                "orgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
                "shortName": "GitHub_M",
                "dateUpdated": "2026-09-21T19:35:15.275Z"
            },
            "descriptions": [
                {
                    "lang": "en",
                    "value": "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 forwards data for a configured non-WebSocket HTTP upgrade before the upstream accepts the upgrade. An unauthenticated HTTP/2 client can place a complete HTTP/1.1 request in extended CONNECT data; Envoy downgrades the request, writes the data unframed to a keep-alive HTTP/1.1 upstream, and returns the socket to the shared pool while the smuggled response remains queued. A different downstream client can then receive the attacker's response. The relevant scope boundary is that webSocket upgrades, plain CONNECT, disabled backend keep-alive, per-downstream pools, and max_requests_per_connection set to 1 are not affected by the demonstrated path. This issue is fixed in versions 1.36.10, 1.37.6, 1.38.4, and 1.39.1."
                }
            ],
            "source": {
                "advisory": "GHSA-3vhp-c83q-jqc2",
                "discovery": "UNKNOWN"
            }
        },
        "adp": [
            {
                "references": [
                    {
                        "url": "https://github.com/envoyproxy/envoy/security/advisories/GHSA-3vhp-c83q-jqc2",
                        "tags": [
                            "exploit"
                        ]
                    }
                ],
                "metrics": [
                    {
                        "other": {
                            "type": "ssvc",
                            "content": {
                                "timestamp": "2026-09-24T22:34:49.061262Z",
                                "id": "CVE-2026-73548",
                                "options": [
                                    {
                                        "Exploitation": "poc"
                                    },
                                    {
                                        "Automatable": "yes"
                                    },
                                    {
                                        "Technical Impact": "partial"
                                    }
                                ],
                                "role": "CISA Coordinator",
                                "version": "2.0.3"
                            }
                        }
                    }
                ],
                "title": "CISA ADP Vulnrichment",
                "providerMetadata": {
                    "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
                    "shortName": "CISA-ADP",
                    "dateUpdated": "2026-09-24T22:35:14.446Z"
                }
            }
        ]
    }
}