The time subsystem in the Linux kernel through 4.9.9, when CONFIG_TIMER_STATS is enabled, allows local users to discover real PID values (as distinguished from PID values inside a PID namespace) by reading the /proc/timer_list file, related to the print_timer function in kernel/time/timer_list.c and the __timer_stats_timer_set_start_info function in kernel/time/timer.c.
The mbcache feature in the ext2 and ext4 filesystem implementations in the Linux kernel before 4.6 mishandles xattr block caching, which allows local users to cause a denial of service (soft lockup) via filesystem operations in environments that use many attributes, as demonstrated by Ceph and Samba.
The VFS subsystem in the Linux kernel 3.x provides an incomplete set of requirements for setattr operations that underspecifies removing extended privilege attributes, which allows local users to cause a denial of service (capability stripping) via a failed invocation of a system call, as demonstrated by using chown to remove a capability from the ping or Wireshark dumpcap program.