The capabilities implementation in the Linux kernel before 3.14.8 does not properly consider that namespaces are inapplicable to inodes, which allows local users to bypass intended chmod restrictions by first creating a user namespace, as demonstrated by setting the setgid bit on a file with group ownership of root.
http://secunia.com/advisories/59220
http://www.exploit-db.com/exploits/33824
http://www.kernel.org/pub/linux/kernel/v3.x/ChangeLog-3.14.8
http://www.openwall.com/lists/oss-security/2014/06/10/4
http://www.securityfocus.com/bid/67988
http://www.securitytracker.com/id/1030394
https://bugzilla.redhat.com/show_bug.cgi?id=1107966
https://github.com/torvalds/linux/commit/23adbe12ef7d3d4195e80800ab36b37bee28cd03
https://source.android.com/security/bulletin/2016-12-01.html