HTTP/2 Unencrypted Connection Vulnerability in Go Programming Language
CVE-2026-56853

Currently unrated

Key Information:

Vendor: Go Standard Library
Status: Net/http
Vendor: CVE Published:; 13 August 2026

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What is CVE-2026-56853?

The vulnerability in the Go programming language's HTTP/2 server arises when it is configured to process unencrypted HTTP/2 connections. During the initial connection phase, the server fails to apply the ReadHeaderTimeout appropriately while inspecting incoming connection bytes for the HTTP/2 client preface. This can lead to potential service disruptions or higher susceptibility to specific types of attacks, as the usual timeout protections are ineffective in this scenario.

Affected Version(s)

net/http 0 < 1.25.13

net/http 1.26.0-0 < 1.26.6

net/http 1.27.0-0 < 1.27.0-rc.3

References

https://go.dev/issue/80205

https://go.dev/cl/795540

https://groups.google.com/g/golang-announce/c/94pEornpRlI

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Timeline

Vulnerability published
Aug 13, 2026
Vulnerability Reserved
Jun 23, 2026

CVE-2026-56853 Data

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