Race condition in the environ_read function in fs/proc/base.c in the Linux kernel before 4.5.4 allows local users to obtain sensitive information from kernel memory by reading a /proc/*/environ file during a process-setup time interval in which environment-variable copying is incomplete.
https://github.com/torvalds/linux/commit/8148a73c9901a8794a50f950083c00ccf97d43b3
https://forums.grsecurity.net/viewtopic.php?f=3&t=4363
https://bugzilla.kernel.org/show_bug.cgi?id=116461
http://www.ubuntu.com/usn/USN-3159-2
http://www.ubuntu.com/usn/USN-3159-1
http://www.securityfocus.com/bid/94138
http://www.kernel.org/pub/linux/kernel/v4.x/ChangeLog-4.5.4