CVE-2026-41568: Moby Docker Engine symlink race condition in docker cp

CVE-2026-41568 · Severity: medium · CVSS 6.1 · Published 2026-06-12

Moby is an open-source framework used to build and run containerized applications like Docker. A flaw in how the software handles file transfers allows a malicious container to create empty files or folders anywhere on the host computer's system. This can be used to cause a permanent service outage by blocking system logins or preventing the Docker service itself from restarting.

Technologies: Docker Engine, github.com/docker/docker (Go), github.com/moby/moby (Go), github.com/moby/moby/v2 (Go). Vendors: Docker, Go.

Quick answers

Is CVE-2026-41568 exploited in the wild?
No. Junglewise Threat Intelligence has no report of CVE-2026-41568 being exploited in the wild.
How severe is CVE-2026-41568?
Medium severity, with a CVSS score of 6.1, published 12 June 2026.
Which products and versions are affected?
Docker Daemon <= 28.5.2; Docker Engine < 29.5.1; Docker Moby <= 28.5.2; github.com/docker/docker (Go) <= 28.5.2, SEMVER:introduced=0, SEMVER:introduced=0,last_affected=28.5.2; and 2 more.
Is there a fix for CVE-2026-41568?
Yes. github.com/moby/moby/v2 (Go): upgrade to 2.0.0-beta.14 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
How is CVE-2026-41568 attacked?
It is attacked with local access, in a software library.
Am I affected by CVE-2026-41568?
Check whether you run Docker Daemon, Docker Engine, Docker Moby or one of the others listed at an affected version. 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.

How to fix

  • github.com/moby/moby/v2 (Go): upgrade to 2.0.0-beta.14 or later
    go get github.com/moby/moby/v2@v2.0.0-beta.14

Technical details

A Time-of-Check Time-of-Use (TOCTOU) race condition exists in the Docker/Moby daemon during the setup of mountpoints for 'docker cp' operations. When copying files into a container, the daemon resolves a path and creates a mountpoint if it doesn't exist; however, a malicious process inside the container can swap a path component with a symlink between these two steps. Because the 'createIfNotExists' function followed symlinks, it would create the file or directory at the symlink's target on the host filesystem with root privileges. This allows for persistent Denial of Service (DoS) by creating files like /etc/nologin or directories where configuration files are expected. The issue is patched in Docker Engine 29.5.1 and Moby 2.0.0-beta.14 by using 'os.Root' to ensure filesystem operations are scoped strictly to the container root.

Affected products

  • Docker Docker Engine < 29.5.1
  • Docker Docker Daemon <= 28.5.2
  • Moby Moby Daemon < 2.0.0-beta.14

Identifiers

  • CVE-2026-41568
  • GHSA-vp62-88p7-qqf5
  • GO-2026-5668

Timeline

  • 2026-05-18: advisory: GitHub advisory published by Moby maintainers
  • 2026-06-12: disclosed: CVE published to NVD

References

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