CVE-2026-56853

Severity CVSS v4.0:

Pending analysis

Type:

Unavailable / Other

Publication date:

13/08/2026

Last modified:

14/08/2026

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.

Impact

Vector 3.x

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H CVSS v3.1 Severity and Metrics:

Base Score: 7.50 HIGH
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Attack Vector (AV): Network
Attack Complexity (AC): Low
Privileges Required (PR): None
User Interaction (UI): None
Scope (S): Unchanged
Confidentiality (C): None
Integrity (I): None
Availability (A): High

Base Score 3.x

7.50

Severity 3.x

HIGH

References to Advisories, Solutions, and Tools

https://go.dev/cl/795540
https://go.dev/issue/80205
https://groups.google.com/g/golang-announce/c/94pEornpRlI
https://pkg.go.dev/vuln/GO-2026-6089