Stack-based buffer overflow in the get_matching_model_microcode function in arch/x86/kernel/cpu/microcode/intel_early.c in the Linux kernel before 4.0 allows context-dependent attackers to gain privileges by constructing a crafted microcode header and leveraging root privileges for write access to the initrd. http://web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-2015-2666
