CVE-2026-48743

7.5 HIGH 0.3% exploit odds Fix listed Other Browser & mail

What it is

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.

At a glance

Exploitability: Can be exploited over the network without logging in. High risk of data tampering.
Exploit odds: 0.3% chance of exploitation in the next 30 days (EPSS).
Fix: A patch, advisory or fixed version is referenced. Upgrade or apply it.

Timeline

2026-06-26 18:17 UTC PublishedDisclosed publicly on CVE.org and NVD
2026-10-25 17:10 UTC Last updatedMost recent change to the record

Why it ranks here

Exploited in the wild: no, CISA does not list it.
Exploit odds: 0.3% in the next 30 days (EPSS).
Severity: 7.5 HIGH (CVSS).
Fix: a patch or advisory is linked.

Details

Published: 2026-06-26 18:17 UTC
Last modified: 2026-10-25 17:10 UTC
Exploit probability: 0.3% · EPSS, next 30 days
Weakness: CWE-444
Record status: Analyzed

Affected

Envoyproxy Envoy < 1.35.13
Envoyproxy Envoy < 1.36.9
Envoyproxy Envoy < 1.37.5
Envoyproxy Envoy < 1.38.3

Attack profile CVSS 3.1 · 7.5

Attack vector: Network
Complexity: High
Privileges needed: None
User interaction: None
Scope: Changed
Confidentiality: Low
Integrity: High
Availability: None

Raw vector

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:L/I:H/A:N

Is it in your code?

Hand this to your coding agent. It searches your project for the affected products and checks versions. Nothing leaves your machine.

Read https://cve-list.com/agent/cve/CVE-2026-48743.md and follow it. Check whether this project is affected by CVE-2026-48743. Read only. Don't change anything and don't upload my code. Tell me yes, no or not sure, with the file as proof.

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Fix and advisories

References

NVD record · CVE.org record