The msr_open function in arch/x86/kernel/msr.c in the Linux kernel before
3.7.6 allows local users to bypass intended capability restrictions by
executing a crafted application as root, as demonstrated by msr32.c.

A flaw was reported in the permission checks done by the Linux kernel for
/dev/cpu/*/msr. A local root user with all capabilities dropped could
exploit this flaw to execute code with full root capabilities.