Vulnerability Details CVE-2026-48743
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.
Exploit prediction scoring system (EPSS) score
EPSS Score 0.003
EPSS Ranking 22.0%
CVSS Severity
CVSS v3 Score 7.5
Products affected by CVE-2026-48743
-
cpe:2.3:a:envoyproxy:envoy:1.35.0
-
cpe:2.3:a:envoyproxy:envoy:1.35.1
-
cpe:2.3:a:envoyproxy:envoy:1.35.10
-
cpe:2.3:a:envoyproxy:envoy:1.35.11
-
cpe:2.3:a:envoyproxy:envoy:1.35.12
-
cpe:2.3:a:envoyproxy:envoy:1.35.2
-
cpe:2.3:a:envoyproxy:envoy:1.35.3
-
cpe:2.3:a:envoyproxy:envoy:1.35.4
-
cpe:2.3:a:envoyproxy:envoy:1.35.5
-
cpe:2.3:a:envoyproxy:envoy:1.35.6
-
cpe:2.3:a:envoyproxy:envoy:1.35.7
-
cpe:2.3:a:envoyproxy:envoy:1.35.8
-
cpe:2.3:a:envoyproxy:envoy:1.35.9
-
cpe:2.3:a:envoyproxy:envoy:1.36.0
-
cpe:2.3:a:envoyproxy:envoy:1.36.1
-
cpe:2.3:a:envoyproxy:envoy:1.36.2
-
cpe:2.3:a:envoyproxy:envoy:1.36.3
-
cpe:2.3:a:envoyproxy:envoy:1.36.4
-
cpe:2.3:a:envoyproxy:envoy:1.36.5
-
cpe:2.3:a:envoyproxy:envoy:1.36.6
-
cpe:2.3:a:envoyproxy:envoy:1.36.7
-
cpe:2.3:a:envoyproxy:envoy:1.36.8
-
cpe:2.3:a:envoyproxy:envoy:1.37.0
-
cpe:2.3:a:envoyproxy:envoy:1.37.1
-
cpe:2.3:a:envoyproxy:envoy:1.37.2
-
cpe:2.3:a:envoyproxy:envoy:1.37.3
-
cpe:2.3:a:envoyproxy:envoy:1.37.4
-
cpe:2.3:a:envoyproxy:envoy:1.38.0
-
cpe:2.3:a:envoyproxy:envoy:1.38.1
-
cpe:2.3:a:envoyproxy:envoy:1.38.2