CVE-2026-48743 Details
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.
A request smuggling vulnerability has been identified in Envoy versions 1.35.11, 1.36.7, 1.37.3, and 1.38.1. The issue arises when Envoy translates a downstream HTTP/3 request that is complete at the transport layer but still carries a nonzero Content-Length into an upstream HTTP/1 request with unresolved body debt. This can lead to the first request's body being consumed by the next Envoy-generated upstream request, causing desynchronization and potential route bypasses.
Users can upgrade to Envoy versions 1.35.13, 1.36.9, 1.37.5, or 1.38.3 to address this vulnerability.
Metrics
CVSS 4.0 Severity and Vector Strings:
No CVSS 4.0 data is available for this CVE.
CVSS 3.x Severity and Vector Strings:
No data available for CVSS Version 2.0 on this CVE.
CISA-ADP
Assessed Jun 29, 2026References to Advisories, Solutions, and Tools
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| URL | Source(s) | Tag(s) |
|---|---|---|
| https://github.com/envoyproxy/envoy/security/advisories/GHSA-8phg-2h2q-jgxf | CISA-ADP | ExploitVendor AdvisoryMitigation |
| https://github.com/envoyproxy/envoy/security/advisories/GHSA-8phg-2h2q-jgxf | [email protected] | ExploitVendor AdvisoryMitigation |
Weakness Enumeration
| CWE-ID | CWE Name | Source |
|---|---|---|
| CWE-444 | Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling') | [email protected] |
Affected Products
| Product | Versions |
|---|---|
| envoyproxy envoy | >= 1.35.0, < 1.35.13 >= 1.36.0, < 1.36.9 >= 1.37.0, < 1.37.5 >= 1.38.0, < 1.38.3 |
CPE
Remediation
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Change History
3 change records found show changes
| Date | Action | Recorded By |
|---|---|---|
| Jun 29, 2026 | Initial Analysis | [email protected] |
| Jun 29, 2026 | CVE Modified | CISA-ADP |
| Jun 26, 2026 | New CVE Received | [email protected] |