CVE-2026-48743

published 2026-06-26

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…

Priority P3 45 high 7.5 CVSS 3.1

AV N AC H PR N UI N S C C L I H A N

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.

Affected

8 ranges

Vendor	Product	Version range	Fixed in
envoyproxy	envoy	—	—
envoyproxy	envoy	—	—
envoyproxy	envoy	—	—
envoyproxy	envoy	—	—
envoyproxy	envoy	>= 1.35.0 < 1.35.13	1.35.13
envoyproxy	envoy	>= 1.36.0 < 1.36.9	1.36.9
envoyproxy	envoy	>= 1.37.0 < 1.37.5	1.37.5
envoyproxy	envoy	>= 1.38.0 < 1.38.3	1.38.3

Stop checking back — get the weekly exploitation signal.

Every Monday: what got weaponized or added to CISA KEV in the last seven days — each CVE cross-linked to its PoC, Nuclei template, and detection rule. Free, one email a week, unsubscribe in one click.

CWE-444