CVE-2026-79994

Docker Sandboxes contains a time-of-check/time-of-use race condition (CWE-367) in the guest-to-host Unix-domain socket relay: a socket path is validated to sit inside the authorized workspace, but the host later reconnects by re-resolving that same pathname. A malicious guest can swap an intermediate directory in the path for a symlink during the window between validation and connection, tricking the host into connecting to an arbitrary AF_UNIX socket outside the shared workspace. Successful exploitation lets the guest read data from, or invoke capabilities exposed by, the targeted host-side socket, with high confidentiality and integrity impact on both the vulnerable component and subsequent systems per the CVSS 4.0 vector (8.7, local attack vector, no privileges or user interaction required). Any developer or environment using Docker Sandboxes to run semi-trusted or untrusted code is affected, since the attacker must already control code inside a sandbox. No public proof of concept exists, the flaw is not on the CISA KEV list, and no exploitation in the wild is known.

What to do: Apply the vendor fix as soon as Docker publishes patched builds, and check Docker's security advisory (assigned by [email protected]) for the exact fixed version of Docker Sandboxes/Docker Desktop. Until patched, treat Sandboxes as isolation-best-effort only: do not run untrusted code, and audit which host AF_UNIX sockets are reachable through the relay, since those become the blast radius of a successful race. Monitor guest workspaces for processes rapidly creating or renaming directories along shared socket paths, which is characteristic of exploitation attempts.