{"id":"CVE-2023-27491","aliases":["BIT-envoy-2023-27491","EUVD-2023-31256","GHSA-5jmv-cw9p-f9rp"],"status":"published","title":"Envoy forwards invalid Http2/Http3 downstream headers","description":"Envoy is an open source edge and service proxy designed for cloud-native applications. Compliant HTTP/1 service should reject malformed request lines. Prior to versions 1.26.0, 1.25.3, 1.24.4, 1.23.6, and 1.22.9, There is a possibility that non compliant HTTP/1 service may allow malformed requests, potentially leading to a bypass of security policies. This issue is fixed in versions 1.26.0, 1.25.3, 1.24.4, 1.23.6, and 1.22.9.","severity":{"version":"3.1","score":5.4,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:N","level":"medium","assessor":"cna","from":"cve"},"epss":{"day":"2026-11-10","score":0.00876,"percentile":0.59307,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":true},"cwes":["CWE-20","CWE-444"],"published":"2023-04-04T18:18:23Z","modified":"2026-10-28T02:30:59Z","fixes":[{"ecosystem":"Bitnami","package":"envoy","fixed_in":["1.22.9","1.23.6","1.24.4","1.25.3"],"sources":["osv"]}],"affected":[{"source":"osv","ecosystem":"Bitnami","package":"envoy","ranges":[{"type":"SEMVER","events":[{"introduced":"0"},{"fixed":"1.22.9"},{"introduced":"1.23.0"},{"fixed":"1.23.6"},{"introduced":"1.24.0"},{"fixed":"1.24.4"},{"introduced":"1.25.0"},{"fixed":"1.25.3"}]}]}],"products":[{"vendor":"envoyproxy","product":"envoy"}],"references":[{"url":"https://github.com/envoyproxy/envoy/security/advisories/GHSA-5jmv-cw9p-f9rp","tags":["x_refsource_CONFIRM","x_transferred","Exploit","Vendor Advisory","advisory"]},{"url":"https://datatracker.ietf.org/doc/html/rfc9113#section-8.3","tags":["x_refsource_MISC","x_transferred","Not Applicable","web"]},{"url":"https://datatracker.ietf.org/doc/html/rfc9114#section-4.3.1","tags":["x_refsource_MISC","x_transferred","Not Applicable","web"]},{"url":"https://www.rfc-editor.org/rfc/rfc9110#section-5.6.2","tags":["x_refsource_MISC","x_transferred","Not Applicable","web"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2023-27491","tags":["web","advisory"]},{"url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2023/27xxx/CVE-2023-27491.json","tags":["advisory"]}],"sources":{"cve":[{"id":"CVE-2023-27491","title":"Envoy forwards invalid Http2/Http3 downstream headers","description":"Envoy is an open source edge and service proxy designed for cloud-native applications. Compliant HTTP/1 service should reject malformed request lines. Prior to versions 1.26.0, 1.25.3, 1.24.4, 1.23.6, and 1.22.9, There is a possibility that non compliant HTTP/1 service may allow malformed requests, potentially leading to a bypass of security policies. This issue is fixed in versions 1.26.0, 1.25.3, 1.24.4, 1.23.6, and 1.22.9.","status":"published","published":"2023-04-04T18:18:23.433Z","modified":"2025-02-11T16:14:43.908Z","cvss":[{"version":"3.1","score":5.4,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:N","level":"medium","assessor":"cna"}],"cwes":["CWE-20"],"updated_at":"2026-11-02T14:35:26.63732Z"}],"euvd":[{"id":"EUVD-2023-31256","description":"Envoy is an open source edge and service proxy designed for cloud-native applications. Compliant HTTP/1 service should reject malformed request lines. Prior to versions 1.26.0, 1.25.3, 1.24.4, 1.23.6, and 1.22.9, There is a possibility that non compliant HTTP/1 service may allow malformed requests, potentially leading to a bypass of security policies. This issue is fixed in versions 1.26.0, 1.25.3, 1.24.4, 1.23.6, and 1.22.9.","status":"published","published":"2023-04-04T18:18:23Z","modified":"2025-02-11T16:14:43Z","cvss":[{"version":"3.1","score":5.4,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:N","level":"medium"}],"updated_at":"2026-11-03T00:03:59.282543Z"}],"nvd":[{"id":"CVE-2023-27491","description":"Envoy is an open source edge and service proxy designed for cloud-native applications. Compliant HTTP/1 service should reject malformed request lines. Prior to versions 1.26.0, 1.25.3, 1.24.4, 1.23.6, and 1.22.9, There is a possibility that non compliant HTTP/1 service may allow malformed requests, potentially leading to a bypass of security policies. This issue is fixed in versions 1.26.0, 1.25.3, 1.24.4, 1.23.6, and 1.22.9.","status":"published","published":"2023-04-04T19:15:07.15Z","modified":"2026-06-17T05:45:19.493Z","cvss":[{"version":"3.1","score":5.4,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:N","level":"medium","assessor":"secondary"},{"version":"3.1","score":9.1,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N","level":"critical","assessor":"primary"}],"cwes":["CWE-20","CWE-444"],"updated_at":"2026-11-02T14:07:51.883939Z"}],"osv":[{"id":"CVE-2023-27491","title":"Envoy forwards invalid Http2/Http3 downstream headers","description":"Envoy is an open source edge and service proxy designed for cloud-native applications. Compliant HTTP/1 service should reject malformed request lines. Prior to versions 1.26.0, 1.25.3, 1.24.4, 1.23.6, and 1.22.9, There is a possibility that non compliant HTTP/1 service may allow malformed requests, potentially leading to a bypass of security policies. This issue is fixed in versions 1.26.0, 1.25.3, 1.24.4, 1.23.6, and 1.22.9.","status":"published","published":"2023-04-04T18:18:23.433Z","modified":"2026-10-28T02:30:59.719143278Z","cvss":[{"version":"3.1","score":5.4,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:N","level":"medium"}],"cwes":["CWE-20"],"updated_at":"2026-11-02T15:44:31.135751Z"},{"id":"BIT-envoy-2023-27491","title":"Envoy forwards invalid Http2/Http3 downstream headers","description":"Envoy is an open source edge and service proxy designed for cloud-native applications. Compliant HTTP/1 service should reject malformed request lines. Prior to versions 1.26.0, 1.25.3, 1.24.4, 1.23.6, and 1.22.9, There is a possibility that non compliant HTTP/1 service may allow malformed requests, potentially leading to a bypass of security policies. This issue is fixed in versions 1.26.0, 1.25.3, 1.24.4, 1.23.6, and 1.22.9.","status":"published","published":"2024-03-06T10:54:12.095Z","modified":"2026-09-08T08:47:22.467986329Z","updated_at":"2026-11-02T15:28:29.563843Z"}]}}