PostgreSQL before 9.1.23, 9.2.x before 9.2.18, 9.3.x before 9.3.14, 9.4.x before 9.4.9, and 9.5.x before 9.5.4 might allow remote authenticated users with the CREATEDB or CREATEROLE role to gain superuser privileges via a (1) " (double quote), (2) \ (backslash), (3) carriage return, or (4) newline character in a (a) database or (b) role name that is mishandled during an administrative operation.
https://www.postgresql.org/docs/current/static/release-9-5-4.html
https://www.postgresql.org/docs/current/static/release-9-4-9.html
https://www.postgresql.org/docs/current/static/release-9-3-14.html
https://www.postgresql.org/docs/current/static/release-9-2-18.html
https://www.postgresql.org/docs/current/static/release-9-1-23.html
https://www.postgresql.org/about/news/1688/
https://security.gentoo.org/glsa/201701-33
https://access.redhat.com/errata/RHSA-2017:2425
http://www.securitytracker.com/id/1036617
http://www.securityfocus.com/bid/92435
http://www.debian.org/security/2016/dsa-3646
http://rhn.redhat.com/errata/RHSA-2016-2606.html
http://rhn.redhat.com/errata/RHSA-2016-1821.html