CVE-2026-56853

high

Description

When a server is configured to support unencrypted HTTP/2, it reads a few bytes from each new connection to see if they contain the HTTP/2 client preface. ReadHeaderTimeout is unexpectedly not being applied when doing this.

References

https://pkg.go.dev/vuln/GO-2026-6089

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

https://go.dev/issue/80205

https://go.dev/cl/795540

Details

Source: Mitre, NVD

Published: 2026-08-13

Updated: 2026-08-14

Risk Information

CVSS v2

Base Score: 7.8

Vector: CVSS2#AV:N/AC:L/Au:N/C:N/I:N/A:C

Severity: High

CVSS v3

Base Score: 7.5

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