CVE-2023-35944

Описание

Envoy is an open source edge and service proxy designed for cloud-native applications. Envoy allows mixed-case schemes in HTTP/2, however, some internal scheme checks are case-sensitive. Prior to versions 1.27.0, 1.26.4, 1.25.9, 1.24.10, and 1.23.12, this can lead to the rejection of requests with mixed-case schemes such as htTp or htTps, or the bypassing of some requests such as https in unencrypted connections. With a fix in versions 1.27.0, 1.26.4, 1.25.9, 1.24.10, and 1.23.12, Envoy will now lowercase scheme values by default, and change the internal scheme checks that were case-sensitive to be case-insensitive. There are no known workarounds for this issue.

A flaw was found in Envoy that allows for mixed-case schemes in HTTP/2. However, some internal scheme checks in Envoy are case-sensitive, leading to incorrect handling of requests and responses with mixed case schemes. For example, if a request with a mixed scheme HTTP is sent to the OAuth2 filter, it will fail the exact-match checks for HTTP and inform the remote endpoint the scheme is HTTP, thus potentially bypassing OAuth2 checks specific to HTTP requests.