{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-48521", "assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa", "state": "PUBLISHED", "assignerShortName": "GitHub_M", "dateReserved": "2026-05-21T16:18:10.619Z", "datePublished": "2026-09-21T19:44:15.389Z", "dateUpdated": "2026-09-21T20:04:16.440Z"}, "containers": {"cna": {"title": "Envoy: HTTP/3 connection pool selection null-derefs in ProdClusterManagerFactory::allocateConnPool when transport_socket_options is null", "problemTypes": [{"descriptions": [{"cweId": "CWE-476", "lang": "en", "description": "CWE-476: NULL Pointer Dereference", "type": "CWE"}]}], "metrics": [{"cvssV3_1": {"attackComplexity": "HIGH", "attackVector": "NETWORK", "availabilityImpact": "HIGH", "baseScore": 5.9, "baseSeverity": "MEDIUM", "confidentialityImpact": "NONE", "integrityImpact": "NONE", "privilegesRequired": "NONE", "scope": "UNCHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H", "version": "3.1"}}], "references": [{"name": "https://github.com/envoyproxy/envoy/security/advisories/GHSA-5vff-j9p4-38j3", "tags": ["x_refsource_CONFIRM"], "url": "https://github.com/envoyproxy/envoy/security/advisories/GHSA-5vff-j9p4-38j3"}, {"name": "https://github.com/envoyproxy/envoy/commit/8ef2da8527fcd17388b046c1add4fb47fb5d0868", "tags": ["x_refsource_MISC"], "url": "https://github.com/envoyproxy/envoy/commit/8ef2da8527fcd17388b046c1add4fb47fb5d0868"}, {"name": "https://github.com/envoyproxy/envoy/commit/cec4899acf03cf551f28611a5f32385648d95f96", "tags": ["x_refsource_MISC"], "url": "https://github.com/envoyproxy/envoy/commit/cec4899acf03cf551f28611a5f32385648d95f96"}, {"name": "https://github.com/envoyproxy/envoy/commit/e7b4839beef7f43594ce8e94c4563c80db04a8a7", "tags": ["x_refsource_MISC"], "url": "https://github.com/envoyproxy/envoy/commit/e7b4839beef7f43594ce8e94c4563c80db04a8a7"}, {"name": "https://github.com/envoyproxy/envoy/commit/f5436f44103fb14cb8ba42a8db0f54a06c98c45a", "tags": ["x_refsource_MISC"], "url": "https://github.com/envoyproxy/envoy/commit/f5436f44103fb14cb8ba42a8db0f54a06c98c45a"}, {"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": "2026-09-21T19:44:15.389Z"}, "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'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."}], "source": {"advisory": "GHSA-5vff-j9p4-38j3", "discovery": "UNKNOWN"}}, "adp": [{"references": [{"url": "https://github.com/envoyproxy/envoy/security/advisories/GHSA-5vff-j9p4-38j3", "tags": ["exploit"]}], "metrics": [{"other": {"type": "ssvc", "content": {"timestamp": "2026-09-21T20:02:39.214503Z", "id": "CVE-2026-48521", "options": [{"Exploitation": "poc"}, {"Automatable": "no"}, {"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": "2026-09-21T20:04:16.440Z"}}]}}