{"id":"CVE-2026-48521","url":"https://www.cyber-defence.io/tools/cve/CVE-2026-48521","generatedAt":"2026-10-28T07:40:58.543Z","title":"With auto_config and HTTP/3 enabled, routine traffic reaching one of those contexts can crash an Envoy worker.","description":"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.","published":"2026-09-21T20:17:25.000Z","lastModified":"2026-10-05T14:09:46.000Z","status":"Analyzed","sourceIdentifier":"security-advisories@github.com","cvss":{"version":"3.1","score":5.9,"severity":"MEDIUM","vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H"},"cwe":["CWE-476"],"affected":["envoyproxy/envoy"],"epss":{"score":0.00739,"percentile":0.54364,"date":"2026-10-27","history":[{"date":"2026-09-22","score":0.00699,"percentile":0.51717}]},"kev":{"listed":false},"exploits":{"count":0,"verified":false,"firstPublished":null,"source":"Exploit-DB (https://gitlab.com/exploit-database/exploitdb)","entries":[]},"verdict":{"level":"low","text":"Lower severity and a low EPSS score (0.74%). Track it; it rarely justifies an emergency change on its own."},"changes":[{"kind":"new","label":"New CVE","at":"2026-09-21T20:17:25.000Z","detail":{"score":"5.9","severity":"MEDIUM","publishedAt":"2026-09-21T20:17:25.463Z"},"summary":"New CVE, medium severity (CVSS 5.9)."}],"references":[{"url":"https://github.com/envoyproxy/envoy/commit/8ef2da8527fcd17388b046c1add4fb47fb5d0868","tags":["Patch"],"source":"security-advisories@github.com"},{"url":"https://github.com/envoyproxy/envoy/commit/cec4899acf03cf551f28611a5f32385648d95f96","tags":["Patch"],"source":"security-advisories@github.com"},{"url":"https://github.com/envoyproxy/envoy/commit/e7b4839beef7f43594ce8e94c4563c80db04a8a7","tags":["Patch"],"source":"security-advisories@github.com"},{"url":"https://github.com/envoyproxy/envoy/commit/f5436f44103fb14cb8ba42a8db0f54a06c98c45a","tags":["Patch"],"source":"security-advisories@github.com"},{"url":"https://github.com/envoyproxy/envoy/releases/tag/v1.36.10","tags":["Release Notes"],"source":"security-advisories@github.com"},{"url":"https://github.com/envoyproxy/envoy/releases/tag/v1.37.6","tags":["Release Notes"],"source":"security-advisories@github.com"},{"url":"https://github.com/envoyproxy/envoy/releases/tag/v1.38.4","tags":["Release Notes"],"source":"security-advisories@github.com"},{"url":"https://github.com/envoyproxy/envoy/releases/tag/v1.39.1","tags":["Release Notes"],"source":"security-advisories@github.com"},{"url":"https://github.com/envoyproxy/envoy/security/advisories/GHSA-5vff-j9p4-38j3","tags":["Exploit","Vendor Advisory"],"source":"security-advisories@github.com"},{"url":"https://github.com/envoyproxy/envoy/security/advisories/GHSA-5vff-j9p4-38j3","tags":["Exploit","Vendor Advisory"],"source":"134c704f-9b21-4f2e-91b3-4a467353bcc0"}],"sources":{"nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-48521","epss":"https://www.first.org/epss/","kev":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog","exploitdb":"https://www.exploit-db.com/"},"licence":"CC BY 4.0 — link back to the CVE Explorer if you publish the results; upstream data remains subject to its own terms."}