A flaw was found in the Linux kernel's handling of clearing SELinux attributes on /proc/pid/attr files before 4.9.10. An empty (null) write to this file can crash the system by causing the system to attempt to access unmapped kernel memory. It was discovered that SELinux in the Linux kernel did not properly handle empty writes to /proc/pid/attr. A local attacker could use this to cause a denial of service (system crash).