HIGH

CVE-2026-78408

Util-linux: util-linux: nsenter --join-cgroup leaks root cgroup migration authority

CVSS v3

7.9

HIGH

EPSS Score

0.2 %

exploit probability, as of 2026-09-29

CISA KEV

known exploited

Exploitation

—

SSVC status

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 termi

Technical details

Published: 2026-09-02
Last Modified: 2026-09-03

Frequently asked questions

What is CVE-2026-78408?

Is CVE-2026-78408 actively exploited?

Active exploitation of CVE-2026-78408 has not been confirmed. Its EPSS score was 0.2% on 2026-09-29, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2026-78408?

CVE-2026-78408 has a CVSS v3 base score of 7.9 (HIGH severity).

Is CVE-2026-78408 affecting your environment?

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