An issue was discovered in GNU Hurd before 0.9 20210404-9. When trying to exec a setuid executable, there's a window of time when the process already has the new privileges, but still refers to the old task and is accessible through the old process port. This can be exploited to get full root access.

An issue was discovered in GNU Hurd before 0.9 20210404-9. libports accepts fake notification messages from any client on any port, which can lead to port use-after-free. This can be exploited for local privilege escalation to get full root access.

An issue was discovered in GNU Hurd before 0.9 20210404-9. The use of an authentication protocol in the proc server is vulnerable to man-in-the-middle attacks, which can be exploited for local privilege escalation to get full root access.