CVE-2026-78408

What it is

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.

At a glance

Exploitability

Can be exploited locally on the machine with a low-privilege account, but needs a user to act. High risk of data tampering, service disruption.

Exploit odds

0.2% chance of exploitation in the next 30 days (EPSS).

Fix

A patch, advisory or fixed version is referenced. Upgrade or apply it.

Timeline

1. 2026-09-02 16:17 UTC PublishedDisclosed publicly on CVE.org and NVD
2. 2026-11-05 03:17 UTC Last updatedMost recent change to the record

Why it ranks here

• Exploited in the wild: no, CISA does not list it.
• Exploit odds: 0.2% in the next 30 days (EPSS).
• Severity: 7.9 HIGH (CVSS).
• Fix: a patch or advisory is linked.

Details

Published

2026-09-02 16:17 UTC

Last modified

2026-11-05 03:17 UTC

Exploit probability

0.2% · EPSS, next 30 days

Weakness

CWE-775

Record status

Awaiting Analysis

Attack profile CVSS 3.1 · 7.9

Attack vector

Local

Complexity

Low

Privileges needed

Low

User interaction

Required

Scope

Changed

Confidentiality

None

Integrity

High

Availability

High

Is it in your code?

Hand this to your coding agent. It searches your project for the affected products and checks versions. Nothing leaves your machine.

Read https://cve-list.com/agent/cve/CVE-2026-78408.md and follow it. Check whether this project is affected by CVE-2026-78408. Read only. Don't change anything and don't upload my code. Tell me yes, no or not sure, with the file as proof.

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