{"id":"BIT-envoy-2020-11767","details":"Istio through 1.5.1 and Envoy through 1.14.1 have a data-leak issue. If there is a TCP connection (negotiated with SNI over HTTPS) to *.example.com, a request for a domain concurrently configured explicitly (e.g., abc.example.com) is sent to the server(s) listening behind *.example.com. The outcome should instead be 421 Misdirected Request. Imagine a shared caching forward proxy re-using an HTTP/2 connection for a large subnet with many users. If a victim is interacting with abc.example.com, and a server (for abc.example.com) recycles the TCP connection to the forward proxy, the victim's browser may suddenly start sending sensitive data to a *.example.com server. This occurs because the forward proxy between the victim and the origin server reuses connections (which obeys the specification), but neither Istio nor Envoy corrects this by sending a 421 error. Similarly, this behavior voids the security model browsers have put in place between domains.","aliases":["CVE-2020-11767"],"modified":"2026-09-08T08:47:08.112856068Z","published":"2024-03-06T11:01:15.092Z","database_specific":{"severity":"Low","cpes":["cpe:2.3:a:envoyproxy:envoy:*:*:*:*:*:*:*:*"]},"references":[{"type":"ADVISORY","url":"https://bugs.chromium.org/p/chromium/issues/detail?id=954160#c5"},{"type":"ADVISORY","url":"https://github.com/envoyproxy/envoy/issues/6767"},{"type":"ADVISORY","url":"https://github.com/istio/istio/issues/13589"},{"type":"ADVISORY","url":"https://github.com/istio/istio/issues/9429"},{"type":"WEB","url":"https://nvd.nist.gov/vuln/detail/CVE-2020-11767"}],"affected":[{"package":{"name":"envoy","ecosystem":"Bitnami","purl":"pkg:bitnami/envoy"},"ranges":[{"type":"SEMVER","events":[{"introduced":"0"},{"fixed":"1.14.2"}]}],"database_specific":{"source":"https://github.com/bitnami/vulndb/tree/main/data/envoy/BIT-envoy-2020-11767.json"},"severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:L/I:N/A:N"}]}],"schema_version":"1.9.0"}