{"id":"CVE-2026-48521","summary":"Envoy: HTTP/3 connection pool selection null-derefs in ProdClusterManagerFactory::allocateConnPool when transport_socket_options is null","details":"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.","aliases":["GHSA-5vff-j9p4-38j3"],"modified":"2026-09-23T08:12:30.711198Z","published":"2026-09-21T19:44:15.389Z","related":["openSUSE-SU-2026:11630-1"],"database_specific":{"cna_assigner":"GitHub_M","cwe_ids":["CWE-476"],"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/48xxx/CVE-2026-48521.json"},"references":[{"type":"WEB","url":"https://github.com/envoyproxy/envoy/releases/tag/v1.36.10"},{"type":"WEB","url":"https://github.com/envoyproxy/envoy/releases/tag/v1.37.6"},{"type":"WEB","url":"https://github.com/envoyproxy/envoy/releases/tag/v1.38.4"},{"type":"WEB","url":"https://github.com/envoyproxy/envoy/releases/tag/v1.39.1"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/48xxx/CVE-2026-48521.json"},{"type":"ADVISORY","url":"https://github.com/envoyproxy/envoy/security/advisories/GHSA-5vff-j9p4-38j3"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-48521"},{"type":"FIX","url":"https://github.com/envoyproxy/envoy/commit/8ef2da8527fcd17388b046c1add4fb47fb5d0868"},{"type":"FIX","url":"https://github.com/envoyproxy/envoy/commit/cec4899acf03cf551f28611a5f32385648d95f96"},{"type":"FIX","url":"https://github.com/envoyproxy/envoy/commit/e7b4839beef7f43594ce8e94c4563c80db04a8a7"},{"type":"FIX","url":"https://github.com/envoyproxy/envoy/commit/f5436f44103fb14cb8ba42a8db0f54a06c98c45a"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://github.com/envoyproxy/envoy","events":[{"introduced":"0"},{"introduced":"6d9bb7d9a85d616b220d1f8fe67b61f82bbdb8d3"},{"introduced":"f1dd21b16c244bda00edfb5ffce577e12d0d2ec2"},{"introduced":"8eea3285d6bdb89f8ea34632cfe7ce1608a8f374"},{"fixed":"053a8989382dd91542ecf0cef8f379b9cb761cdd"},{"fixed":"cf413bdb37b36d3ffbe570b8a48760abe2b588f5"},{"fixed":"ef2d997c1b022cf8b849a1d3521fbf234d79ca26"},{"fixed":"b579d07d3ad7ee11d32b105e91a5a39ad24718d7"},{"fixed":"8ef2da8527fcd17388b046c1add4fb47fb5d0868"},{"fixed":"cec4899acf03cf551f28611a5f32385648d95f96"},{"fixed":"e7b4839beef7f43594ce8e94c4563c80db04a8a7"},{"fixed":"f5436f44103fb14cb8ba42a8db0f54a06c98c45a"}],"database_specific":{"source":["AFFECTED_FIELD","REFERENCES"],"extracted_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"}]}}],"versions":["v1.39.0","v1.36.9","v1.38.3","v1.37.5","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","v1.35.0","v1.34.0","v1.33.0","v1.32.0","v1.31.0","v1.30.0","v1.29.0","v1.28.0","v1.27.0","v1.26.0","v1.25.0","v1.24.0","v1.23.0","v1.22.0","v1.21.0","v1.20.0","v1.19.0","v1.18.2","v1.18.1","v1.18.0","v1.17.0","v1.16.0","v1.15.0","v1.14.0","v1.13.0","v1.12.0","v1.11.0","v1.10.0","v1.9.0","v1.8.0","v1.7.0","v1.6.0","v1.5.0","v1.4.0","v1.3.0","v1.2.0","v1.1.0","v1.0.0"],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-48521.json","vanir_signatures_modified":"2026-09-23T08:12:30Z","vanir_signatures":[{"digest":{"line_hashes":["331824448694435672560591242338064462004","158556610975848630418676663142864097967","179162782142876328382935475676910509273","85603905592347423099626928801413229054"],"threshold":0.9},"id":"CVE-2026-48521-3780e8f7","signature_type":"Line","signature_version":"v1","source":"https://github.com/envoyproxy/envoy/commit/f5436f44103fb14cb8ba42a8db0f54a06c98c45a","target":{"file":"source/common/upstream/cluster_manager_impl.cc"},"deprecated":false},{"source":"https://github.com/envoyproxy/envoy/commit/e7b4839beef7f43594ce8e94c4563c80db04a8a7","target":{"file":"source/common/upstream/cluster_manager_impl.cc"},"deprecated":false,"digest":{"line_hashes":["331824448694435672560591242338064462004","158556610975848630418676663142864097967","179162782142876328382935475676910509273","85603905592347423099626928801413229054"],"threshold":0.9},"id":"CVE-2026-48521-7c2d9524","signature_type":"Line","signature_version":"v1"},{"id":"CVE-2026-48521-b32793bd","signature_type":"Line","signature_version":"v1","source":"https://github.com/envoyproxy/envoy/commit/cec4899acf03cf551f28611a5f32385648d95f96","target":{"file":"source/common/upstream/cluster_manager_impl.cc"},"deprecated":false,"digest":{"line_hashes":["331824448694435672560591242338064462004","158556610975848630418676663142864097967","179162782142876328382935475676910509273","85603905592347423099626928801413229054"],"threshold":0.9}},{"source":"https://github.com/envoyproxy/envoy/commit/8ef2da8527fcd17388b046c1add4fb47fb5d0868","target":{"file":"source/common/upstream/cluster_manager_impl.cc"},"deprecated":false,"digest":{"line_hashes":["331824448694435672560591242338064462004","158556610975848630418676663142864097967","179162782142876328382935475676910509273","85603905592347423099626928801413229054"],"threshold":0.9},"id":"CVE-2026-48521-b42179e3","signature_type":"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