CVE-2026-78408
Publication date 2 September 2026
Last updated 9 November 2026
Ubuntu priority
Description
The nsenter --join-cgroup option opens the target cgroup.procs file as root and leaves that file descriptor open across later namespace and credential changes and across execve(). Because the kernel checks later cgroup migrations using the credentials from the original open, a program run in an attacker-controlled target can inherit root's ability to move host processes between cgroups. After a privileged operator uses --join-cgroup against that target, an unprivileged user can migrate and terminate unrelated root processes.
Status
| Package | Ubuntu Release | Status |
|---|---|---|
| util-linux | 26.10 stonking |
Needs evaluation
|
| 26.04 LTS resolute |
Vulnerable
|
|
| 24.04 LTS noble |
Not affected
|
|
| 22.04 LTS jammy |
Not affected
|
|
| 20.04 LTS focal |
Needs evaluation
|
|
| 18.04 LTS bionic |
Needs evaluation
|
|
| 16.04 LTS xenial |
Needs evaluation
|
|
| 14.04 LTS trusty |
Needs evaluation
|
Severity score breakdown
CVSS version: CVSS v3.0
Base score
7.9 · High
Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:C/C:N/I:H/A:H