Описание
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.
Отчет
Affected versions: util-linux v2.40 through v2.42.2. The --join-cgroup option was introduced in v2.40; earlier releases (including util-linux 2.38) are not affected. Fixed in v2.41.6 and v2.42.3.
Меры по смягчению последствий
Upgrade to util-linux v2.41.6, v2.42.3, or later. Until a fix is applied, do not run nsenter --join-cgroup (including nsenter --target PID --all --join-cgroup) against untrusted processes or namespaces. The fix closes the cgroup.procs descriptor immediately after joining, and opens it with O_CLOEXEC.
Затронутые пакеты
| Платформа | Пакет | Состояние | Рекомендация | Релиз |
|---|---|---|---|---|
| Red Hat Enterprise Linux 10 | util-linux | Affected | ||
| Red Hat Enterprise Linux 7 | util-linux | Not affected | ||
| Red Hat Enterprise Linux 8 | util-linux | Not affected | ||
| Red Hat Enterprise Linux 9 | rhel8/flatpak-runtime | Not affected | ||
| Red Hat Enterprise Linux 9 | rhel8/flatpak-sdk | Not affected | ||
| Red Hat Enterprise Linux 9 | util-linux | Not affected | ||
| Red Hat OpenShift Container Platform 4 | rhcos | Not affected | ||
| Red Hat Hardened Images | util-linux-main-2.42.2-3.4.hum1 | Fixed | RHSA-2026:63162 | 03.09.2026 |
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Дополнительная информация
Статус:
EPSS
7.9 High
CVSS3
Связанные уязвимости
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.
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.
Util-linux: util-linux: nsenter --join-cgroup leaks root cgroup migration authority
The nsenter --join-cgroup option opens the target cgroup.procs file as ...
EPSS
7.9 High
CVSS3