CVE-2026-56853

Publication date 13 August 2026

Last updated 19 August 2026

Ubuntu priority

Medium

Why this priority?

Cvss 3 Severity Score

7.5 · High

Score breakdown

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.

Read the notes from the security team

Status

Package Ubuntu Release Status
golang 26.10 stonking Not in release
26.04 LTS resolute Not in release
24.04 LTS noble Not in release
22.04 LTS jammy Not in release
golang-1.6 26.10 stonking Not in release
26.04 LTS resolute Not in release
24.04 LTS noble Not in release
22.04 LTS jammy Not in release
16.04 LTS xenial
Needs evaluation
golang-1.8 26.10 stonking Not in release
26.04 LTS resolute Not in release
24.04 LTS noble Not in release
22.04 LTS jammy Not in release
18.04 LTS bionic
Needs evaluation
golang-1.9 26.10 stonking Not in release
26.04 LTS resolute Not in release
24.04 LTS noble Not in release
22.04 LTS jammy Not in release
18.04 LTS bionic
Needs evaluation
golang-1.10 26.10 stonking Not in release
26.04 LTS resolute Not in release
24.04 LTS noble Not in release
22.04 LTS jammy Not in release
18.04 LTS bionic
Needs evaluation
16.04 LTS xenial
Needs evaluation
14.04 LTS trusty
Needs evaluation
golang-1.13 26.10 stonking Not in release
26.04 LTS resolute Not in release
24.04 LTS noble Not in release
22.04 LTS jammy
Needs evaluation
20.04 LTS focal
Needs evaluation
18.04 LTS bionic
Needs evaluation
16.04 LTS xenial
Needs evaluation
golang-1.14 26.10 stonking Not in release
26.04 LTS resolute Not in release
24.04 LTS noble Not in release
22.04 LTS jammy Not in release
20.04 LTS focal
Needs evaluation
golang-1.16 26.10 stonking Not in release
26.04 LTS resolute Not in release
24.04 LTS noble Not in release
22.04 LTS jammy Not in release
20.04 LTS focal
Needs evaluation
18.04 LTS bionic
Needs evaluation
golang-1.17 26.10 stonking Not in release
26.04 LTS resolute Not in release
24.04 LTS noble Not in release
22.04 LTS jammy
Needs evaluation
golang-1.18 26.10 stonking Not in release
26.04 LTS resolute Not in release
24.04 LTS noble Not in release
22.04 LTS jammy
Needs evaluation
20.04 LTS focal
Needs evaluation
18.04 LTS bionic
Needs evaluation
16.04 LTS xenial
Needs evaluation
golang-1.20 26.10 stonking Not in release
26.04 LTS resolute Not in release
24.04 LTS noble Not in release
22.04 LTS jammy
Needs evaluation
20.04 LTS focal
Needs evaluation
golang-1.21 26.10 stonking Not in release
26.04 LTS resolute Not in release
24.04 LTS noble
Needs evaluation
22.04 LTS jammy
Needs evaluation
20.04 LTS focal
Needs evaluation
golang-1.22 26.10 stonking Not in release
26.04 LTS resolute Not in release
24.04 LTS noble
Not affected
22.04 LTS jammy
Not affected
20.04 LTS focal
Not affected
golang-1.23 26.10 stonking Not in release
26.04 LTS resolute
Needs evaluation
24.04 LTS noble
Needs evaluation
22.04 LTS jammy
Needs evaluation
golang-1.24 26.10 stonking Not in release
26.04 LTS resolute
Needs evaluation
24.04 LTS noble
Needs evaluation
22.04 LTS jammy
Needs evaluation
golang-1.25 26.10 stonking Not in release
26.04 LTS resolute
Needs evaluation
24.04 LTS noble
Needs evaluation
22.04 LTS jammy
Needs evaluation

Notes

mdeslaur

Packages built using golang need to be rebuilt once the vulnerability has been fixed. This CVE entry does not list packages that need rebuilding outside of the main repository or the Ubuntu variants with PPA overlays. Warning: do not include nullboot in the list of no-change rebuilds after fixing an issue in golang.

Severity score breakdown

CVSS version: CVSS v3.0

Base score 7.5 · High

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

References

Other references

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