A Local Privilege Escalation vulnerability (from any user to root) was found in polkit's pkexec, a SUID-root program that is installed by default on every major Linux distribution.

A flaw was found in the way the "flags" member of the new pipe buffer structure was lacking proper initialization in copypagetoiterpipe and pushpipe functions in the Linux kernel and could thus contain stale values. An unprivileged local user could use this flaw to write to pages in the page cache backed by read only files and as such escalate their privileges on the system.

A vulnerability was found in cgroupreleaseagentwrite in kernel/cgroup/cgroup-v1.c in the Linux kernel. In this flaw, under certain circumstances, the cgroups v1 releaseagent feature can be used to escalate privilege and bypass namespace isolation unexpectedly.

Upstream Commit:

https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=24f6008564183aa120d07c03d9289519c2fe02af