arch/x86/kernel/entry_64.S in the Linux kernel before 3.19.2 does not prevent the TS_COMPAT flag from reaching a user-mode task, which might allow local users to bypass the seccomp or audit protection mechanism via a crafted application that uses the (1) fork or (2) close system call, as demonstrated by an attack against seccomp before 3.16.
git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git%3Ba=commit%3Bh=956421fbb74c3a6261903f3836c0740187cf038b
lists.opensuse.org/opensuse-security-announce/2015-09/msg00004.html
lists.opensuse.org/opensuse-security-announce/2015-09/msg00018.html
lists.opensuse.org/opensuse-security-announce/2015-09/msg00021.html
rhn.redhat.com/errata/RHSA-2015-1137.html
rhn.redhat.com/errata/RHSA-2015-1138.html
rhn.redhat.com/errata/RHSA-2015-1221.html
www.debian.org/security/2015/dsa-3237
www.kernel.org/pub/linux/kernel/v3.x/ChangeLog-3.19.2
www.openwall.com/lists/oss-security/2015/04/02/1
www.oracle.com/technetwork/topics/security/linuxbulletinjan2016-2867209.html
www.securitytracker.com/id/1032413
www.ubuntu.com/usn/USN-2631-1
www.ubuntu.com/usn/USN-2632-1
bugzilla.redhat.com/show_bug.cgi?id=1208598
github.com/torvalds/linux/commit/956421fbb74c3a6261903f3836c0740187cf038b