{"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": "2026-09-21T19:35:15.275Z"}, "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"}}}}

{}

{"affected": [{"affectedData": [{"product": "envoy", "vendor": "envoyproxy", "versions": [{"status": "affected", "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"}]}], "source": "[email protected]"}], "cveTags": [], "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."}], "id": "CVE-2026-73548", "lastModified": "2026-09-21T20:17:28.397", "metrics": {"cvssMetricV31": [{"cvssData": {"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"}, "exploitabilityScore": 3.9, "impactScore": 3.6, "source": "[email protected]", "type": "Secondary"}]}, "published": "2026-09-21T20:17:28.397", "references": [{"source": "[email protected]", "url": "https://github.com/envoyproxy/envoy/commit/309855626966cff176155c821043ed3b44671361"}, {"source": "[email protected]", "url": "https://github.com/envoyproxy/envoy/commit/3c7998545a9c9fb3933a4bc1907d92f0e752bc2b"}, {"source": "[email protected]", "url": "https://github.com/envoyproxy/envoy/commit/4633b8cce3d15b8734eefe232e30c12b0140b91c"}, {"source": "[email protected]", "url": "https://github.com/envoyproxy/envoy/commit/bd6711f2617658e28dfa3df3dace6bfe3cfc0766"}, {"source": "[email protected]", "url": "https://github.com/envoyproxy/envoy/releases/tag/v1.36.10"}, {"source": "[email protected]", "url": "https://github.com/envoyproxy/envoy/releases/tag/v1.37.6"}, {"source": "[email protected]", "url": "https://github.com/envoyproxy/envoy/releases/tag/v1.38.4"}, {"source": "[email protected]", "url": "https://github.com/envoyproxy/envoy/releases/tag/v1.39.1"}, {"source": "[email protected]", "url": "https://github.com/envoyproxy/envoy/security/advisories/GHSA-3vhp-c83q-jqc2"}], "sourceIdentifier": "[email protected]", "vulnStatus": "Received", "weaknesses": [{"description": [{"lang": "en", "value": "CWE-444"}], "source": "[email protected]", "type": "Primary"}]}

{"bugzilla": {"description": "envoy: envoy: connection poisoning through generic non-WebSocket HTTP upgrade requests", "id": "2512096", "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2512096"}, "csaw": false, "cvss3": {"cvss3_base_score": "7.5", "cvss3_scoring_vector": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N", "status": "draft"}, "cwe": "CWE-444", "details": ["No description is available for this CVE."], "name": "CVE-2026-73548", "package_state": [{"cpe": "cpe:/a:redhat:service_mesh:3", "fix_state": "Affected", "package_name": "openshift-service-mesh/istio-proxyv2-rhel9", "product_name": "OpenShift Service Mesh 3"}], "public_date": "2026-08-26T13:00:00Z", "references": ["https://www.cve.org/CVERecord?id=CVE-2026-73548\nhttps://nvd.nist.gov/vuln/detail/CVE-2026-73548"], "threat_severity": "Important"}

{"affected": [{"configurations": [{"platform": null, "status": "affected", "versions": null}], "enrichment": {"confidence": 75.0, "confidence_source": "inferred", "scores": [{"score": 75.0, "source": "inferred"}, {"score": 81.0, "source": "matching"}]}, "product": "envoy", "vendor": "envoyproxy"}], "created": "2026-09-01T14:45:04.117613+00:00", "updated": "2026-09-21T20:30:18.218513+00:00", "vendors": ["envoyproxy", "envoyproxy$PRODUCT$envoy"]}