The filesystem implementation in the Linux kernel through 4.8.2 preserves the setgid bit during a setxattr call, which allows local users to gain group privileges by leveraging the existence of a setgid program with restrictions on execute permissions.
http://marc.info/?l=linux-fsdevel&m=147162313630259&w=2
http://rhn.redhat.com/errata/RHSA-2017-0817.html
http://www.openwall.com/lists/oss-security/2016/08/26/3
http://www.securityfocus.com/bid/92659
http://www.securitytracker.com/id/1038201
http://www.spinics.net/lists/linux-fsdevel/msg98328.html
http://www.ubuntu.com/usn/USN-3146-1
http://www.ubuntu.com/usn/USN-3146-2
http://www.ubuntu.com/usn/USN-3147-1
https://access.redhat.com/errata/RHSA-2017:1842
https://access.redhat.com/errata/RHSA-2017:2077
https://access.redhat.com/errata/RHSA-2017:2669
https://bugzilla.redhat.com/show_bug.cgi?id=1368938
https://github.com/torvalds/linux/commit/073931017b49d9458aa351605b43a7e34598caef
https://source.android.com/security/bulletin/2017-04-01
https://support.f5.com/csp/article/K31603170?utm_source=f5support&utm_medium=RSS
Source: MITRE
Published: 2016-10-16
Updated: 2018-01-05
Type: CWE-285
Base Score: 3.6
Vector: AV:L/AC:L/Au:N/C:P/I:P/A:N
Impact Score: 4.9
Exploitability Score: 3.9
Severity: LOW
Base Score: 4.4
Vector: CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N
Impact Score: 2.5
Exploitability Score: 1.8
Severity: MEDIUM