fs/namespace.c in the Linux kernel through 3.16.1 does not properly restrict clearing MNTNODEV, MNTNOSUID, and MNTNOEXEC and changing MNTATIME_MASK during a remount of a bind mount, which allows local users to gain privileges, interfere with backups and auditing on systems that had atime enabled, or cause a denial of service (excessive filesystem updating) on systems that had atime disabled via a "mount -o remount" command within a user namespace.