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CVE-2026-78408

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

No known exploitation. EPSS puts it in the 5th percentile. Only a workaround so far.

CVSS 3.17.9HighEPSS percentile5th0.2% chance in 30 daysCISA KEVNot listedNo confirmed exploitation
No public exploit knownFixWorkaroundNo fixed build yet

Published Updated Sources: CVE.org, NVD

NVD CVE.org

What to do

No fixed build is published yet. The vendor describes a workaround.

Check it yourselfA free OpenVAS check exists for this CVE. Run it against your hosts.Is your organisation exposed?Request an assessment to establish which checks fit your systems.

What it is

From the CVE record

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.

In plain language

No plain-language summary for this CVE yet.

Exploitation

Where each signal puts this CVE on the scale from published to confirmed exploited.

EPSS5th
CISA KEV

Not in the catalog. CISA has not confirmed exploitation.

Public exploits

No public exploit or proof of concept found in the sources we track.

EPSS

0.2% chance of exploitation activity in the next 30 days, which ranks it in the 5th percentile of scored CVEs.

Exploit Prediction Scoring System, FIRST.org. A probability, not a confirmation.

Lifecycle

15 events over 6 days, from the signal feeds we watch.

  1. OpenVAS check added
  2. Workaround availablerecord updated
  3. Workaround availablerecord updated
  4. Workaround availableworkaround available, record updated, record updated
  5. Workaround availablepublished, published, weakness classified, weakness classified, record updated

Affected products

And 3 more affected products. See all after sign-in

Technical detail

CVSS 3.1 vector

Open in the CVSS calculator

CVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:C/C:N/I:H/A:H

Scored 7.9 by NVD.

How it is reached

  • Attack Vector LocalRequires local access to the vulnerable system (e.g. local login, malicious file)
  • Attack Complexity LowNo special conditions — the attack can be reliably reproduced
  • Privileges Required LowRequires basic user-level privileges
  • User Interaction RequiredA user must click a link, open a file, or perform some action

Scope

  • Scope ChangedThe exploit can affect other components (e.g. sandbox escape, host compromise from VM)

Impact if exploited

  • Confidentiality NoneNo confidentiality impact
  • Integrity HighTotal loss of integrity — attacker can modify any data in the component
  • Availability HighTotal denial of service — the component is completely unavailable

Weaknesses

Sources

References in the record

And 2 more references. See all after sign-in

In the news

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