CVE-2023-0386: Linux Kernel privilege escalation in OverlayFS

CVE-2023-0386 · Severity: critical · CVSS 7.8 · Exploited in the wild · Published 2025-06-17

A security vulnerability has been identified in the Linux kernel's OverlayFS component, which is commonly used for managing file systems in container environments and live operating systems. This flaw allows a person who already has limited access to a computer to gain full administrative (root) control. Such an escalation of privileges could allow an attacker to bypass security restrictions, access sensitive data, or disrupt system operations.

Technologies: Linux Kernel. Vendors: Linux.

Quick answers

Is CVE-2023-0386 exploited in the wild?
Yes. CVE-2023-0386 is known to be exploited in the wild, first recorded on 17 June 2025. Treat it as urgent.
How severe is CVE-2023-0386?
Critical severity, with a CVSS score of 7.8, published 17 June 2025.
Which products and versions are affected?
Linux Linux Kernel OverlayFS subsystem; CanonicalHeader Ubuntu Linux 18.04 LTS, 20.04 LTS, 22.04 LTS; Debian Debian Linux 10.0.
Is there a fix for CVE-2023-0386?
No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.
How is CVE-2023-0386 attacked?
It is attacked with local access, in an operating system.
Am I affected by CVE-2023-0386?
Check whether you run Linux Kernel. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

Technical details

An improper ownership management vulnerability (CWE-282) exists in the Linux kernel's OverlayFS subsystem. The flaw occurs during the process of copying a file with setuid capabilities from a 'nosuid' mount into another mount point. Due to a bug in UID mapping, the kernel fails to properly restrict the execution of these files, allowing a local, unprivileged attacker to execute a specially crafted file with elevated privileges. This effectively results in a local privilege escalation (LPE) to root. Patches have been released for major distributions including Debian and Ubuntu.

Affected products

  • Linux Linux Kernel OverlayFS subsystem
  • CanonicalHeader Ubuntu Linux 18.04 LTS, 20.04 LTS, 22.04 LTS
  • Debian Debian Linux 10.0

Timeline

  • 2023-06-01: advisory: Debian LTS security advisory published
  • 2025-06-17: kev added: Added to CISA Known Exploited Vulnerabilities catalog
  • 2025-06-17: disclosed: Public disclosure date listed in advisory

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