FreeBSD Security Advisory - The MOV SS and POP SS instructions inhibit debug exceptions until the instruction boundary following the next instruction. If that instruction is a system call or similar instruction that transfers control to the operating system, the debug exception will be handled in the kernel context instead of the user context. An authenticated local attacker may be able to read sensitive data in kernel memory, control low-level operating system functions, or may panic the system.
436c2453ffbf42d86b402970ed7a42fbf8c2b6d77a9f356bfdc4d651e22df44f