FreeBSD Security Advisory – A special combination of sysarch(2) arguments, specify a request to uninstall a set of descriptors from the LDT. The start descriptor is cleared and the number of descriptors are provided. Due to invalid use of a signed intermediate value in the bounds checking during argument validity verification, unbound zero’ing of the process LDT and adjacent memory can be initiated from usermode. This vulnerability could cause the kernel to panic. In addition it is possible to perform a local Denial of Service against the system by unprivileged processes.