The do_remount function in fs/namespace.c in the Linux kernel through 3.16.1 does not maintain the MNT_LOCK_READONLY bit across a remount of a bind mount, which allows local users to bypass an intended read-only restriction and defeat certain sandbox protection mechanisms via a "mount -o remount" command within a user namespace.

fs/namespace.c in the Linux kernel through 3.16.1 does not properly restrict clearing MNT_NODEV, MNT_NOSUID, and MNT_NOEXEC and changing MNT_ATIME_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.