CVE-2026-56853

Apply ReadHeaderTimeout when doing unencrypted HTTP/2 check in net/http

State: Published
Severity: 7.5 High
Published: Aug 13, 2026
Updated: Aug 14, 2026
Reserved: Jun 23, 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.

Scores

CVSS	Score	Vector	Source
3.1	7.5 High	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H	CISA-ADP

Weaknesses

CWE-770 Allocation of Resources Without Limits or Throttling

Affected Products

Product	Versions
net/httpGo standard library	before 1.25.13Affected 1.26.0-0 to before 1.26.6Affected 1.27.0-0 to before 1.27.0-rc.3Affected

References

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