An issue was discovered in Malwarebytes before 4.0 on macOS. A malicious application was able to perform a privileged action within the Malwarebytes launch daemon. The privileged service improperly validated XPC connections by relying on the PID instead of the audit token.

An attacker can construct a situation where the same PID is used for running two different programs at different times, by leveraging a race condition during crafted use of posix_spawn.