{"attribution":"This product uses data from the NVD API but is not endorsed or certified by the NVD.","cve":{"id":"CVE-2026-48521","sourceIdentifier":"security-advisories@github.com","published":"2026-09-21T20:17:25.463","lastModified":"2026-10-05T14:09:45.933","vulnStatus":"Analyzed","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'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."}],"affected":[{"source":"security-advisories@github.com","affectedData":[{"vendor":"envoyproxy","product":"envoy","versions":[{"version":"\u003c 1.36.10","status":"affected"},{"version":"\u003e= 1.37.0, \u003c 1.37.6","status":"affected"},{"version":"\u003e= 1.38.0, \u003c 1.38.4","status":"affected"},{"version":"\u003e= 1.39.0, \u003c 1.39.1","status":"affected"}]}]}],"metrics":{"cvssMetricV31":[{"source":"security-advisories@github.com","type":"Secondary","cvssData":{"version":"3.1","vectorString":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H","baseScore":5.9,"baseSeverity":"MEDIUM","attackVector":"NETWORK","attackComplexity":"HIGH","privilegesRequired":"NONE","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"NONE","integrityImpact":"NONE","availabilityImpact":"HIGH"},"exploitabilityScore":2.2,"impactScore":3.6}],"ssvcV203":[{"source":"134c704f-9b21-4f2e-91b3-4a467353bcc0","ssvcData":{"timestamp":"2026-09-21T20:02:39.214503Z","id":"CVE-2026-48521","options":[{"exploitation":"poc"},{"automatable":"no"},{"technicalImpact":"partial"}],"role":"CISA Coordinator","version":"2.0.3"}}]},"weaknesses":[{"source":"security-advisories@github.com","type":"Primary","description":[{"lang":"en","value":"CWE-476"}]}],"configurations":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:a:envoyproxy:envoy:*:*:*:*:*:*:*:*","versionEndExcluding":"1.36.10","matchCriteriaId":"6A420B14-9ADA-4F6B-ACAA-3045E8690F04"},{"vulnerable":true,"criteria":"cpe:2.3:a:envoyproxy:envoy:*:*:*:*:*:*:*:*","versionStartIncluding":"1.37.0","versionEndExcluding":"1.37.6","matchCriteriaId":"1AD376F3-22D7-4BFB-B00C-BD68F464436F"},{"vulnerable":true,"criteria":"cpe:2.3:a:envoyproxy:envoy:*:*:*:*:*:*:*:*","versionStartIncluding":"1.38.0","versionEndExcluding":"1.38.4","matchCriteriaId":"840E030F-8746-4DBD-87C0-5DF7896294CC"},{"vulnerable":true,"criteria":"cpe:2.3:a:envoyproxy:envoy:*:*:*:*:*:*:*:*","versionStartIncluding":"1.39.0","versionEndExcluding":"1.39.1","matchCriteriaId":"B5C1C594-8142-4F51-BE50-1AF50FD07129"}]}]}],"references":[{"url":"https://github.com/envoyproxy/envoy/commit/8ef2da8527fcd17388b046c1add4fb47fb5d0868","source":"security-advisories@github.com","tags":["Patch"]},{"url":"https://github.com/envoyproxy/envoy/commit/cec4899acf03cf551f28611a5f32385648d95f96","source":"security-advisories@github.com","tags":["Patch"]},{"url":"https://github.com/envoyproxy/envoy/commit/e7b4839beef7f43594ce8e94c4563c80db04a8a7","source":"security-advisories@github.com","tags":["Patch"]},{"url":"https://github.com/envoyproxy/envoy/commit/f5436f44103fb14cb8ba42a8db0f54a06c98c45a","source":"security-advisories@github.com","tags":["Patch"]},{"url":"https://github.com/envoyproxy/envoy/releases/tag/v1.36.10","source":"security-advisories@github.com","tags":["Release Notes"]},{"url":"https://github.com/envoyproxy/envoy/releases/tag/v1.37.6","source":"security-advisories@github.com","tags":["Release Notes"]},{"url":"https://github.com/envoyproxy/envoy/releases/tag/v1.38.4","source":"security-advisories@github.com","tags":["Release Notes"]},{"url":"https://github.com/envoyproxy/envoy/releases/tag/v1.39.1","source":"security-advisories@github.com","tags":["Release Notes"]},{"url":"https://github.com/envoyproxy/envoy/security/advisories/GHSA-5vff-j9p4-38j3","source":"security-advisories@github.com","tags":["Exploit","Vendor Advisory"]},{"url":"https://github.com/envoyproxy/envoy/security/advisories/GHSA-5vff-j9p4-38j3","source":"134c704f-9b21-4f2e-91b3-4a467353bcc0","tags":["Exploit","Vendor Advisory"]}]}}