Reference page — cumulative record through Wednesday, August 19, 2026 UTC. Reference pages update as the archive grows; only dated daily editions are immutable pages of record.
envoyproxy envoy — Envoy: HTTP/3 to HTTP/1 request smuggling via headers-only request with nonzero Content-Length
AV AC PR UI S C I A CVSS EPSS %ile KEV
N H N N C L H N 7.5 .0022 12.5 —
AFFECTED
Product Versions Fixed
envoy >= 1.38.0, < 1.38.1 – —
TIMELINE
May 22 Reserved by GitHub_M
Jun 26 EXPLOIT PUBLISHED — CVE-2026-48743 (envoyproxy envoy). Public exploit reference added.
Jun 26 Published (CNA: GitHub_M)
Description
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.
Lifecycle
Complete event history — 3 events, chronological
| Date | Event | Detail |
|---|
| May 22, 2026 | Reserved | Reserved by GitHub_M |
| June 26, 2026 | EXPLOIT PUBLISHED | EXPLOIT PUBLISHED — CVE-2026-48743 (envoyproxy envoy). Public exploit reference added. |
| June 26, 2026 | Published | Published (CNA: GitHub_M) |
Affected
Affected products and packages — 1 row
| Vendor | Product / Package | Ecosystem | Version introduced | Fixed |
|---|
| envoyproxy | envoy | — | >= 1.38.0, < 1.38.1 | — |
About this page
This is a reference page, not a dated page of record. It assembles the complete lifecycle of CVE-2026-48743 from the CVE Program record, NVD enrichment, the CISA KEV catalog, EPSS, and OSV advisories. The box score's numbers (CVSS, EPSS, KEV status) are current as of Wednesday, August 19, 2026 UTC and are re-derived as the archive grows; only dated daily editions are immutable pages of record. The authoritative source for this identifier is cve.org.