Docker Fixes Critical Sandbox Flaws Allowing Host File Writes and Socket Access

Docker has patched two critical vulnerabilities in Docker Sandboxes, which are used to run AI coding agents and other workloads inside isolated microVM environments. CVE-2026-77179 has a CVSSv4 score of 9.4 and affects macOS releases from 0.28.0 to before 0.42.0. CVE-2026-79994, rated 8.7, affects versions from 0.37.0 to before 0.42.0 across platforms. The article says there is no confirmed exploitation or public proof of concept for either flaw.

CVE-2026-77179 involves the virtio-fs host server improperly following symlinks when reopening unlinked files. A malicious guest could replace a parent directory with a symlink and write arbitrary files on the macOS host as the virtual machine monitor user. CVE-2026-79994 affects the guest-to-host Unix-domain-socket relay: a symlink race could allow the relay to connect to an arbitrary host AF_UNIX socket outside the authorised workspace.

Docker addressed both issues in version 0.42.0 and users are advised to upgrade. Where immediate updating is not possible, the article recommends using clone mode and avoiding read-write host mounts in sandbox configurations.