CVE-2026-56853

Public on 2026-08-13
Modified on 2026-08-15
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.
Severity
Important severity
Important
See what this means
CVSS v3 Base Score
7.5
See breakdown

Affected Packages

Platform Package Release Date Advisory Status
Amazon Linux 2 - Core golang Pending Fix
Amazon Linux 2 - Golang1.11 Extra golang No Fix Planned
Amazon Linux 2 - Golang1.19 Extra golang No Fix Planned
Amazon Linux 2 - Golang1.9 Extra golang No Fix Planned
Amazon Linux 2023 golang Pending Fix

CVSS Scores

Score Type Score Vector
Amazon Linux CVSSv3 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

References

FAQs regarding Amazon Linux ALAS/CVE Severity Red Hat: CVE-2026-56853 Mitre: CVE-2026-56853