Secunia Research Advisory – A vulnerability has been identified in OpenBSD allowing a malicious root user to escalate privileges. The problem is that the root user may set the semaphore limit to a high value, which causes an integer overflow. This could be exploited to bypass the security level access control (securelevel) specified at boot time.
You can download this advisory from the following link: https://packetstormsecurity.com/files/download/31643/semaphore.txt
Source: https://packetstormsecurity.com/files/31643/semaphore.txt.html