CVE-2026-48743

Описание

Envoy is an open source edge and service proxy designed for cloud-native applications. Prior to 1.35.11, 1.36.7, 1.37.3, and 1.38.1, Envoy can translate a downstream HTTP/3 request that is complete at the transport layer (HEADERS with FIN / headers-only close) but still carries a nonzero Content-Length into a complete upstream HTTP/1 request with unresolved body debt. In an HTTP/1 upstream deployment where the origin replies before reading the declared body and keeps the connection reusable, the beginning of the next Envoy-generated upstream request can be consumed as the first request's body. The remaining bytes are then parsed by the origin as a new HTTP/1 request. This was reproduced as a route-bypass/desync: direct /pwn was denied by Envoy, but the second downstream H3 stream received the response for backend-parsed GET /pwn HTTP/1.1. This vulnerability is fixed in 1.35.11, 1.36.7, 1.37.3, and 1.38.1.

A flaw was found in Envoy, an open source edge and service proxy. This vulnerability occurs when Envoy translates an HTTP/3 request that is complete at the transport layer but still carries a nonzero Content-Length into an HTTP/1 request for an upstream server. If the upstream server responds before fully reading the declared body, a subsequent Envoy-generated request can be misinterpreted as part of the previous one. This can lead to a request desynchronization, allowing an attacker to bypass security policies and access unauthorized resources.