Nixpkgs security tracker

Untriaged

Permalink CVE-2026-48743

7.5 HIGH

CVSS version (CVSS): 3.1
Attack Vector (AV): Network (N)
Attack Complexity (AC): High (H)
Privileges Required (PR): None (N)
User Interaction (UI): None (N)
Scope (S): Changed (C)
Confidentiality (C): Low (L)
Integrity (I): High (H)
Availability (A): None (N)
Modified Attack Vector (MAV): Network (N)
Modified Attack Complexity (MAC): High (H)
Modified Privileges Required (MPR): None (N)
Modified User Interaction (MUI): None (N)
Modified Confidentiality (MC): Low (L)
Modified Scope (MS): Changed (C)
Modified Integrity (MI): High (H)
Modified Availability (MA): None (N)

created 2 months ago Activity log

Created suggestion 2 months ago

Envoy: HTTP/3 to HTTP/1 request smuggling via headers-only request with nonzero Content-Length

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.