High 7.5Published Aug 13, 2026

CVE-2026-56853Apply ReadHeaderTimeout when doing unencrypted HTTP/2 check in net/http

Updated under an hour ago (2026-10-19 06:25 UTC)

Does this affect you?

It affects Go standard library net/http. Add what you run to find out whether that includes you.

No exploitation reported and no EPSS estimate yet.

Do this next

Start free and add your stack

Free account, 1 product

Every CVE for Go standard library net/http

Exploited in the last 30 days

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.

CVSS: 7.5 HIGH (v3.1, CISA ADP)CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Weakness (CWE): CWE-770
Known exploited: Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days): Not loaded for this CVE
Assigned by: Go
NVD analysis: Awaiting Analysis
Record last updated: Aug 14, 2026
First seen by InfoSec Signals: Oct 9, 2026

Affected products

Affected products

Go standard library net/http go_standard_library:net_http (from the name)	before 1.25.13; from 1.26.0-0 before 1.26.6; 1.27.0-0 builds before 1.27.0-rc.3	CNA record

References

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

The CVE record on cve.org NVD's entry

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.