# CVE-2026-78408: Util-linux: util-linux: nsenter --join-cgroup leaks root cgroup migration authority CVE-2026-78408 is fixed in 16 products on 1 platform, first by RHSA-2026:93461, released September 2, 2026. It is not reported as exploited. Patch Radar priority: High. - Web page: https://patchblox.com/security/cve/CVE-2026-78408 - Priority: High - CVSS: 8.0 (Important) - EPSS: 0.0024 - CISA KEV: not listed - Exploited (vendor report): no - Publicly disclosed: no - Published: Sep 2, 2026 - Weakness: Missing Release of File Descriptor or Handle after Effective Lifetime - Vendor advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-78408 ## 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. ## Where it's fixed | Platform | Product | Fixed in | Fix | Released | |---|---|---|---|---| | Linux | libblkid almalinux 10 | 2.40.2-18.el10_2.20 | [ALSA-2026:93461](https://patchblox.com/security/data/fix/linux/alsa-2026-93461.md) | Nov 7, 2026 | | Linux | libblkid ol 10 | 0:2.40.2-18.0.1.el10_2.20 | [ELSA-2026-93461](https://patchblox.com/security/data/fix/linux/elsa-2026-93461.md) | Nov 7, 2026 | | Linux | libblkid-devel almalinux 10 | 2.40.2-18.el10_2.20 | [ALSA-2026:93461](https://patchblox.com/security/data/fix/linux/alsa-2026-93461.md) | Nov 7, 2026 | | Linux | libblkid-devel ol 10 | 0:2.40.2-18.0.1.el10_2.20 | [ELSA-2026-93461](https://patchblox.com/security/data/fix/linux/elsa-2026-93461.md) | Nov 7, 2026 | | Linux | libfdisk almalinux 10 | 2.40.2-18.el10_2.20 | [ALSA-2026:93461](https://patchblox.com/security/data/fix/linux/alsa-2026-93461.md) | Nov 7, 2026 | | Linux | libfdisk ol 10 | 0:2.40.2-18.0.1.el10_2.20 | [ELSA-2026-93461](https://patchblox.com/security/data/fix/linux/elsa-2026-93461.md) | Nov 7, 2026 | | Linux | libfdisk-devel almalinux 10 | 2.40.2-18.el10_2.20 | [ALSA-2026:93461](https://patchblox.com/security/data/fix/linux/alsa-2026-93461.md) | Nov 7, 2026 | | Linux | libfdisk-devel ol 10 | 0:2.40.2-18.0.1.el10_2.20 | [ELSA-2026-93461](https://patchblox.com/security/data/fix/linux/elsa-2026-93461.md) | Nov 7, 2026 | | Linux | libmount almalinux 10 | 2.40.2-18.el10_2.20 | [ALSA-2026:93461](https://patchblox.com/security/data/fix/linux/alsa-2026-93461.md) | Nov 7, 2026 | | Linux | libmount ol 10 | 0:2.40.2-18.0.1.el10_2.20 | [ELSA-2026-93461](https://patchblox.com/security/data/fix/linux/elsa-2026-93461.md) | Nov 7, 2026 | | Linux | libmount-devel almalinux 10 | 2.40.2-18.el10_2.20 | [ALSA-2026:93461](https://patchblox.com/security/data/fix/linux/alsa-2026-93461.md) | Nov 7, 2026 | | Linux | libmount-devel ol 10 | 0:2.40.2-18.0.1.el10_2.20 | [ELSA-2026-93461](https://patchblox.com/security/data/fix/linux/elsa-2026-93461.md) | Nov 7, 2026 | | Linux | libsmartcols almalinux 10 | 2.40.2-18.el10_2.20 | [ALSA-2026:93461](https://patchblox.com/security/data/fix/linux/alsa-2026-93461.md) | Nov 7, 2026 | | Linux | libsmartcols ol 10 | 0:2.40.2-18.0.1.el10_2.20 | [ELSA-2026-93461](https://patchblox.com/security/data/fix/linux/elsa-2026-93461.md) | Nov 7, 2026 | | Linux | libsmartcols-devel almalinux 10 | 2.40.2-18.el10_2.20 | [ALSA-2026:93461](https://patchblox.com/security/data/fix/linux/alsa-2026-93461.md) | Nov 7, 2026 | | Linux | libsmartcols-devel ol 10 | 0:2.40.2-18.0.1.el10_2.20 | [ELSA-2026-93461](https://patchblox.com/security/data/fix/linux/elsa-2026-93461.md) | Nov 7, 2026 | | Linux | libuuid almalinux 10 | 2.40.2-18.el10_2.20 | [ALSA-2026:93461](https://patchblox.com/security/data/fix/linux/alsa-2026-93461.md) | Nov 7, 2026 | | Linux | libuuid ol 10 | 0:2.40.2-18.0.1.el10_2.20 | [ELSA-2026-93461](https://patchblox.com/security/data/fix/linux/elsa-2026-93461.md) | Nov 7, 2026 | | Linux | libuuid-devel almalinux 10 | 2.40.2-18.el10_2.20 | [ALSA-2026:93461](https://patchblox.com/security/data/fix/linux/alsa-2026-93461.md) | Nov 7, 2026 | | Linux | libuuid-devel ol 10 | 0:2.40.2-18.0.1.el10_2.20 | [ELSA-2026-93461](https://patchblox.com/security/data/fix/linux/elsa-2026-93461.md) | Nov 7, 2026 | | Linux | python-libmount opensuse-leap 16.0 | 2.41.1-160000.5.1 | [OPENSUSE-SU-2026:21905-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-21905-1.md) | Sep 22, 2026 | | Linux | python-libmount sles 16.0 | 2.41.1-160000.5.1 | [SUSE-SU-2026:23870-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-23870-1.md) | Sep 22, 2026 | | Linux | python3-libmount almalinux 10 | 2.40.2-18.el10_2.20 | [ALSA-2026:93461](https://patchblox.com/security/data/fix/linux/alsa-2026-93461.md) | Nov 7, 2026 | | Linux | python3-libmount ol 10 | 0:2.40.2-18.0.1.el10_2.20 | [ELSA-2026-93461](https://patchblox.com/security/data/fix/linux/elsa-2026-93461.md) | Nov 7, 2026 | | Linux | util-linux Debian 14 | 2.42.4-1 | [DEBIAN-CVE-2026-78408](https://patchblox.com/security/data/fix/linux/debian-cve-2026-78408.md) | Sep 17, 2026 | | Linux | util-linux RHEL 10 | 2.40.2-18.el10_2.20 | [RHSA-2026:93461](https://patchblox.com/security/data/fix/linux/rhsa-2026-93461.md) | Sep 2, 2026 | | Linux | util-linux almalinux 10 | 2.40.2-18.el10_2.20 | [ALSA-2026:93461](https://patchblox.com/security/data/fix/linux/alsa-2026-93461.md) | Nov 7, 2026 | | Linux | util-linux ol 10 | 0:2.40.2-18.0.1.el10_2.20 | [ELSA-2026-93461](https://patchblox.com/security/data/fix/linux/elsa-2026-93461.md) | Nov 7, 2026 | | Linux | util-linux opensuse-leap 16.0 | 2.41.1-160000.5.1 | [OPENSUSE-SU-2026:21905-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-21905-1.md) | Sep 22, 2026 | | Linux | util-linux rocky 10 | 0:2.40.2-18.el10_2.20 | [RLSA-2026:93461](https://patchblox.com/security/data/fix/linux/rlsa-2026-93461.md) | Nov 7, 2026 | | Linux | util-linux sles 16.0 | 2.41.1-160000.5.1 | [SUSE-SU-2026:23870-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-23870-1.md) | Sep 22, 2026 | | Linux | util-linux-core almalinux 10 | 2.40.2-18.el10_2.20 | [ALSA-2026:93461](https://patchblox.com/security/data/fix/linux/alsa-2026-93461.md) | Nov 7, 2026 | | Linux | util-linux-core ol 10 | 0:2.40.2-18.0.1.el10_2.20 | [ELSA-2026-93461](https://patchblox.com/security/data/fix/linux/elsa-2026-93461.md) | Nov 7, 2026 | | Linux | util-linux-systemd opensuse-leap 16.0 | 2.41.1-160000.5.1 | [OPENSUSE-SU-2026:21905-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-21905-1.md) | Sep 22, 2026 | | Linux | util-linux-systemd sles 16.0 | 2.41.1-160000.5.1 | [SUSE-SU-2026:23870-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-23870-1.md) | Sep 22, 2026 | | Linux | uuidd almalinux 10 | 2.40.2-18.el10_2.20 | [ALSA-2026:93461](https://patchblox.com/security/data/fix/linux/alsa-2026-93461.md) | Nov 7, 2026 | | Linux | uuidd ol 10 | 0:2.40.2-18.0.1.el10_2.20 | [ELSA-2026-93461](https://patchblox.com/security/data/fix/linux/elsa-2026-93461.md) | Nov 7, 2026 | --- Data as of 2026-11-08T19:12:23Z UTC. 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