CVE-2026-78408: Red Hat Enterprise Linux 10

High severity, CVSS 7.9. EPSS: 0.2% chance of exploitation in the next 30 days.

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.

Affected products

• Red Hat Red Hat Enterprise Linux 10
• Red Hat Red Hat Enterprise Linux 7
• Red Hat Red Hat Enterprise Linux 8
• Red Hat Red Hat Enterprise Linux 9
• Red Hat Red Hat Hardened Images: before 2.42.2-3.4.hum1 (fixed in 2.42.2-3.4.hum1)
• Red Hat Red Hat Openshift Container Platform 4

Published 2026-09-02. Last modified 2026-09-05.