Envoy is a cloud-native, open source edge and service proxy. Envoy exposed an out-of-memory (OOM) vector from the mirror response, since async HTTP client will buffer the response with an unbounded buffer.

Envoy is a cloud-native, open source edge and service proxy. There is a use-after-free in `HttpConnectionManager` (HCM) with `EnvoyQuicServerStream` that can crash Envoy. An attacker can exploit this vulnerability by sending a request without `FIN`, then a `RESET_STREAM` frame, and then after receiving the response, closing the connection.

Envoy is a cloud-native, open source edge and service proxy. Envoyproxy with a Brotli filter can get into an endless loop during decompression of Brotli data with extra input.

Envoy is a cloud-native, open source edge and service proxy. There is a crash at `QuicheDataReader::PeekVarInt62Length()`. It is caused by integer underflow in the `QuicStreamSequencerBuffer::PeekRegion()` implementation.

Envoy is a cloud-native, open source edge and service proxy. A crash was observed in `EnvoyQuicServerStream::OnInitialHeadersComplete()` with following call stack. It is a use-after-free caused by QUICHE continuing push request headers after `StopReading()` being called on the stream. As after `StopReading()`, the HCM's `ActiveStream` might have already be destroyed and any up calls from QUICHE could potentially cause use after free.

Envoy is a cloud-native, open source edge and service proxy. A theoretical request smuggling vulnerability exists through Envoy if a server can be tricked into adding an upgrade header into a response. Per RFC https://www.rfc-editor.org/rfc/rfc7230#section-6.7 a server sends 101 when switching protocols. Envoy incorrectly accepts a 200 response from a server when requesting a protocol upgrade, but 200 does not indicate protocol switch. This opens up the possibility of request smuggling through Envoy if the server can be tricked into adding the upgrade header to the response.

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.

Envoy is an open source edge and service proxy designed for cloud-native applications. Prior to versions 1.27.0, 1.26.4, 1.25.9, 1.24.10, and 1.23.12, the CORS filter will segfault and crash Envoy when the `origin` header is removed and deleted between `decodeHeaders`and `encodeHeaders`. Versions 1.27.0, 1.26.4, 1.25.9, 1.24.10, and 1.23.12 have a fix for this issue. As a workaround, do not remove the `origin` header in the Envoy configuration.

Envoy is an open source edge and service proxy designed for cloud-native applications. Prior to versions 1.27.0, 1.26.4, 1.25.9, 1.24.10, and 1.23.12, gRPC access loggers using listener's global scope can cause a `use-after-free` crash when the listener is drained. Versions 1.27.0, 1.26.4, 1.25.9, 1.24.10, and 1.23.12 have a fix for this issue. As a workaround, disable gRPC access log or stop listener update.

Envoy is an open source edge and service proxy designed for cloud-native applications. Prior to versions 1.27.0, 1.26.4, 1.25.9, 1.24.10, and 1.23.12, a malicious client is able to construct credentials with permanent validity in some specific scenarios. This is caused by the some rare scenarios in which HMAC payload can be always valid in OAuth2 filter's check. Versions 1.27.0, 1.26.4, 1.25.9, 1.24.10, and 1.23.12 have a fix for this issue. As a workaround, avoid wildcards/prefix domain wildcards in the host's domain configuration.

Envoy is a cloud-native high-performance edge/middle/service proxy. Envoy’s HTTP/2 codec may leak a header map and bookkeeping structures upon receiving `RST_STREAM` immediately followed by the `GOAWAY` frames from an upstream server. In nghttp2, cleanup of pending requests due to receipt of the `GOAWAY` frame skips de-allocation of the bookkeeping structure and pending compressed header. The error return [code path] is taken if connection is already marked for not sending more requests due to `GOAWAY` frame. The clean-up code is right after the return statement, causing memory leak. Denial of service through memory exhaustion. This vulnerability was patched in versions(s) 1.26.3, 1.25.8, 1.24.9, 1.23.11.