Privilege Context Switching Error in Util-linux - CVE-2026-78408
Published: September 2, 2026
Vulnerability identifier: #VU146720
CSH Severity: High
CVSS v4: 6.8 [CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:A/VC:N/VI:H/VA:H/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-78408
CWE-ID: CWE-270
Exploitation vector: Local access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a local user to migrate host root processes into attacker-controlled cgroups and cause a denial of service.
The vulnerability exists due to improper access control in sys-utils/nsenter.c when handling the --join-cgroup operation and executing a program after namespace and credential transitions. A local user can cause a privileged operator to invoke nsenter against an attacker-controlled target to inherit a root-opened cgroup.procs file descriptor and use it to migrate unrelated host root processes into an attacker-controlled cgroup and cause a denial of service.
User interaction is required, and exploitation depends on cgroup v2 with unprivileged user namespaces enabled.
Affected software
Util-linux
How to mitigate CVE-2026-78408
Install security update from vendor's website.
Util-linux - addressed in versions 2.41.6, 2.42.3