Ubuntu USN · USN-8416-1

Go Networking vulnerability

Published: Tue, 09 Jun 2026 18:01

CVE-2026-39821

Summary

Go Networking could allow unintended access to network services.

Details

It was discovered that Go Networking incorrectly handled certain Punycode-encoded labels in the idna package. An attacker could possibly use this issue to bypass hostname-based access restrictions.

Recommended actions per Ubuntu release

StackPatch playbook auto-generated per release codename and per affected package.

Ubuntu bionic

golang-golang-x-net-dev→1:0.0+git20170629.c81e7f2+dfsg-2ubuntu0.1~esm3apt_upgrade_esm
Fixed at 1:0.0+git20170629.c81e7f2+dfsg-2ubuntu0.1~esm3 — ESM-only. Enable Ubuntu Pro (free for 5 personal machines) or treat as watch item.
```
sudo pro attach <token>
sudo apt-get update
sudo apt-get install --only-upgrade -y golang-golang-x-net-dev=1:0.0+git20170629.c81e7f2+dfsg-2ubuntu0.1~esm3
```
Sign up at https://ubuntu.com/pro. Free for personal + small-team use.
golang-go.net-dev→1:0.0+git20170629.c81e7f2+dfsg-2ubuntu0.1~esm3apt_upgrade_esm
Fixed at 1:0.0+git20170629.c81e7f2+dfsg-2ubuntu0.1~esm3 — ESM-only. Enable Ubuntu Pro (free for 5 personal machines) or treat as watch item.
```
sudo pro attach <token>
sudo apt-get update
sudo apt-get install --only-upgrade -y golang-go.net-dev=1:0.0+git20170629.c81e7f2+dfsg-2ubuntu0.1~esm3
```
Sign up at https://ubuntu.com/pro. Free for personal + small-team use.
golang-golang-x-net-dev→1:0.0+git20170629.c81e7f2+dfsg-2ubuntu0.1~esm3apt_upgrade_esm
Fixed at 1:0.0+git20170629.c81e7f2+dfsg-2ubuntu0.1~esm3 — ESM-only. Enable Ubuntu Pro (free for 5 personal machines) or treat as watch item.
```
sudo pro attach <token>
sudo apt-get update
sudo apt-get install --only-upgrade -y golang-golang-x-net-dev=1:0.0+git20170629.c81e7f2+dfsg-2ubuntu0.1~esm3
```
Sign up at https://ubuntu.com/pro. Free for personal + small-team use.

Ubuntu focal

golang-golang-x-net-dev→1:0.0+git20190811.74dc4d7+dfsg-1ubuntu0.1~esm3apt_upgrade_esm
Fixed at 1:0.0+git20190811.74dc4d7+dfsg-1ubuntu0.1~esm3 — ESM-only. Enable Ubuntu Pro (free for 5 personal machines) or treat as watch item.
```
sudo pro attach <token>
sudo apt-get update
sudo apt-get install --only-upgrade -y golang-golang-x-net-dev=1:0.0+git20190811.74dc4d7+dfsg-1ubuntu0.1~esm3
```
Sign up at https://ubuntu.com/pro. Free for personal + small-team use.
golang-go.net-dev→1:0.0+git20190811.74dc4d7+dfsg-1ubuntu0.1~esm3apt_upgrade_esm
Fixed at 1:0.0+git20190811.74dc4d7+dfsg-1ubuntu0.1~esm3 — ESM-only. Enable Ubuntu Pro (free for 5 personal machines) or treat as watch item.
```
sudo pro attach <token>
sudo apt-get update
sudo apt-get install --only-upgrade -y golang-go.net-dev=1:0.0+git20190811.74dc4d7+dfsg-1ubuntu0.1~esm3
```
Sign up at https://ubuntu.com/pro. Free for personal + small-team use.
golang-golang-x-net-dev→1:0.0+git20190811.74dc4d7+dfsg-1ubuntu0.1~esm3apt_upgrade_esm
Fixed at 1:0.0+git20190811.74dc4d7+dfsg-1ubuntu0.1~esm3 — ESM-only. Enable Ubuntu Pro (free for 5 personal machines) or treat as watch item.
```
sudo pro attach <token>
sudo apt-get update
sudo apt-get install --only-upgrade -y golang-golang-x-net-dev=1:0.0+git20190811.74dc4d7+dfsg-1ubuntu0.1~esm3
```
Sign up at https://ubuntu.com/pro. Free for personal + small-team use.

Are YOU affected by USN-8416-1?

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curl https://mindsparkstack.com/scan.sh | bash

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