Ubuntu 26.04 Google Guest Agent Important Denial Service Issues USN-8447-3

ubuntu

June 22, 2026

Several security issues were fixed in Google Guest Agent.

Summary

Several security issues were fixed in Google Guest Agent.

Software Description:

- google-guest-agent: Google Compute Engine Guest Agent

Details:

USN-8447-1 fixed vulnerabilities in Go Cryptography. This update provides

the corresponding updates for Go Cryptography code embedded in Google

Guest Agent.

Original advisory details:

It was discovered that Go Cryptography did not properly handle SSH global

request responses. A remote attacker could possibly use this issue to cause

a denial of service. (CVE-2026-39830)

It was discovered that Go Cryptography did not properly verify user

presence when using FIDO/U2F security keys. An attacker could possibly use

this issue to bypass user presence verification for hardware security keys.

This issue only affected Ubuntu 20.04 LTS, Ubuntu 22.04 LTS, Ubuntu 24.04

LTS, and Ubuntu 26.04 LTS. (CVE-2026-39831)

It was discovered that Go Cryptography did not properly serialize SSH agent

key constraint extensions. An attacker could poss...

Read the Full Advisory

Topics Covered

security advisory denial service software update Ubuntu important Google Guest Agent

Update Instructions

The problem can be corrected by updating your system to the following
package versions:

Ubuntu 26.04 LTS
  google-guest-agent              20250506.01-0ubuntu2.1

Ubuntu 25.10
  google-guest-agent              20250506.01-0ubuntu1.2

Ubuntu 24.04 LTS
  google-guest-agent              20250116.00-0ubuntu1~24.04.4

Ubuntu 22.04 LTS
  google-guest-agent              20250116.00-0ubuntu1~22.04.3

Ubuntu 20.04 LTS
  google-guest-agent              20250116.00-0ubuntu1~20.04.0+esm3
                                  Available with Ubuntu Pro

Ubuntu 18.04 LTS
  google-guest-agent              20241011.01-0ubuntu1~18.04.0+esm3
                                  Available with Ubuntu Pro

Ubuntu 16.04 LTS
  google-guest-agent              20240716.00-0ubuntu1~16.04.0+esm3
                                  Available with Ubuntu Pro

In general, a standard system update will make all the necessary changes.