CVE-2026-78408Util-linux: util-linux: nsenter --join-cgroup leaks root cgroup migration authority
Updated under an hour ago ()
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It affects Red Hat Hardened Images and 2 other products. Add what you run to find out whether that includes you.
No exploitation reported and no EPSS estimate yet.
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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.
- CVSS
- 7.9 HIGH (v3.1, CNA)CVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:C/C:N/I:H/A:H
- Weakness (CWE)
- CWE-775
- Known exploited
- Not in CISA's KEV catalog
- EPSS (exploitation in the next 30 days)
- Not loaded for this CVE
- Assigned by
- redhat
- NVD analysis
- Awaiting Analysis
- Record last updated
- Sep 5, 2026
- First seen by InfoSec Signals
- Oct 9, 2026
Affected products
Red Hat Red Hat Hardened Images redhat:hummingbird | from 2.42.2-3.4.hum1 not affected | CNA record |
Red Hat Red Hat Enterprise Linux 10 redhat:enterprise_linux | 10 | CNA record |
Red Hat Red Hat OpenShift Container Platform 4 redhat:openshift | 4 | CNA record |
References
- https://access.redhat.com/errata/RHSA-2026:63162vendor-advisory, x-refsource-redhat
- https://access.redhat.com/security/cve/CVE-2026-78408vdb-entry, x-refsource-redhat
- https://bugzilla.redhat.com/show_bug.cgi?id=2522497issue-tracking, x-refsource-redhat
- https://github.com/util-linux/util-linux/security/advisories/GHSA-55fx-f4gg-cfhj
- http://www.openwall.com/lists/oss-security/2026/09/05/2
The CVE record on cve.org NVD's entry
The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.