{"id":"CVE-2021-28683","details":"An issue was discovered in Envoy through 1.71.1. There is a remotely exploitable NULL pointer dereference and crash in TLS when an unknown TLS alert code is received.","aliases":["BIT-envoy-2021-28683"],"modified":"2026-08-07T15:15:35.425551Z","published":"2021-05-20T17:15:07.713Z","related":["GHSA-r22g-5f3x-xjgg","GHSA-xw4q-6pj2-5gfg"],"references":[{"type":"ADVISORY","url":"https://blog.envoyproxy.io"},{"type":"ADVISORY","url":"https://github.com/envoyproxy/envoy/releases"},{"type":"ADVISORY","url":"https://github.com/envoyproxy/envoy/security/advisories/GHSA-r22g-5f3x-xjgg"},{"type":"ADVISORY","url":"https://github.com/envoyproxy/envoy/security/advisories/GHSA-xw4q-6pj2-5gfg"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://github.com/envoyproxy/envoy","events":[{"introduced":"e98e41a8e168af7acae8079fc0cd68155f699aa3"},{"last_affected":"d6a4496e712d7a2335b26e2f76210d5904002c26"}],"database_specific":{"cpe":["cpe:2.3:a:envoyproxy:envoy:1.16.2:*:*:*:*:*:*:*","cpe:2.3:a:envoyproxy:envoy:1.17.1:*:*:*:*:*:*:*"],"extracted_events":[{"introduced":"1.16.2"},{"last_affected":"1.16.2"},{"introduced":"1.17.1"},{"last_affected":"1.17.1"}],"source":"CPE_STRING"}}],"versions":["1.16.2","1.17.1"],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2021-28683.json"}}],"schema_version":"1.8.0","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H"}]}