tip on multiple BSD-based operating systems allows local users to cause a denial of service (execution prevention) by using flock() to lock the /var/log/acculog file.
The uipc system calls (uipc_syscalls.c) in OpenBSD 2.9 and 3.0 provide user mode return instead of versus rval kernel mode values to the fdrelease function, which allows local users to cause a denial of service and trigger a null dereference.
OpenBSD 7.3 before errata 014 is missing an argument-count bounds check in console terminal emulation. This could cause incorrect memory access and a kernel crash after receiving crafted DCS or CSI terminal escape sequences.