The insertmodule function in runtime/staprun/staprunfuncs.c in the systemtap runtime tool (staprun) in SystemTap before 1.6 does not properly validate a module when loading it, which allows local users to gain privileges via a race condition between the signature validation and the module initialization.

A flaw was discovered in systemtap's handling of DWARF expressions where it did not guard against two cases of divide by zero. This can result in a kernel div-by-zero message and possible busywait during stap module shutdown. A div-by-zero could cause the kernel to panic and if the kernel reboot on panic flag was set (paniconoops), it would cause the system to reboot.

In order to trigger this flaw, it would require a user with staprun or stapdev group membership (or root privileges) to run a particular stap script operation on a hand-corrupted elf program.