Espreto

**Name of the Vulnerable Software and Affected Versions** Canonical Multipass for macOS versions prior to 1.16.3 **Description** An incomplete fix for a previous issue allows a local attacker to achieve local privilege escalation. Five binaries located in `/Library/Application Support/com.canonical.multipass/bin/` (`multipass`, `qemu-img`, `qemu-system-aarch64`, `qemu-system-x86 64`, and `sshfs server`) remain writable by the installing user. The root LaunchDaemon `com.canonical.multipassd.plist` configures a `PATH` environment variable that prioritizes this directory and invokes these binaries by their bare names. A local attacker can replace one of these auxiliary binaries with a malicious wrapper, which is then executed with root privileges when triggered by the root daemon during routine operations, such as during a `multipass launch` command. **Recommendations** Update to version 1.16.3 or later.

**Name of the Vulnerable Software and Affected Versions** Canonical Multipass versions prior to 1.16.3 **Description** The host-side SFTP server component (sshfs server), which runs with root privileges on the host, contains a path containment bypass in the `validate path()` function. This function uses a plain string prefix comparison for requested paths but fails to perform path separator validation or dot-dot (..) normalization. A local attacker with root privileges inside a guest virtual machine can bypass the FUSE (Filesystem in Userspace) layer—a mechanism that allows non-privileged users to create their own file systems—by injecting raw SFTP frames, such as an `SSH FXP OPEN` request, directly into the `sshfs server` process pipes via procfs. By using directory traversal sequences that match the allowed mount prefix, the attacker can force the host process to open files outside the designated boundary, enabling the reading of arbitrary files on the host filesystem and resulting in a virtual machine escape. **Recommendations** Update to version 1.16.3 or later.