high · 7.9

Util-linux: util-linux: nsenter --join-cgroup leaks root cgroup migration authority

CVE-2026-78408 · published 2 Sept 2026

How serious is it

  • Severity: high, CVSS score 7.9 out of 10.
  • No exploit prediction (EPSS) score yet.
  • Not on the CISA list of exploited vulnerabilities.
  • No public exploit in Exploit-DB.

Is your app affected by CVE-2026-78408?

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Who is affected

  • Red Hat Red Hat Hardened Images
  • 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 Enterprise Linux 9
  • Red Hat Red Hat Enterprise Linux 9
  • Red Hat Red Hat OpenShift Container Platform 4
  • Red Hat Red Hat OpenShift Container Platform 4

How to check

  1. Find out whether you run the affected product and which version, then compare it with the versions above.

How to fix

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  1. Apply the vendor's update or mitigation from the references below. If there is none yet, limit exposure of the affected service until there is.
  2. If a vulnerable version was live, check your logs and rotate the secrets that server could read.

The advisory

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.

Check your whole app

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References

Merged from CVE List. Last updated 29 Oct 2026. All vulnerabilities · RSS · JSON

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