PostgreSQL versions 8.4 - 9.6 are vulnerable to information leak in pg_user_mappings view which discloses foreign server passwords to any user having USAGE privilege on the associated foreign server.
https://www.postgresql.org/about/news/1746/
https://security.gentoo.org/glsa/201710-06
https://access.redhat.com/errata/RHSA-2017:2425
https://access.redhat.com/errata/RHSA-2017:1983
https://access.redhat.com/errata/RHSA-2017:1838
https://access.redhat.com/errata/RHSA-2017:1678
https://access.redhat.com/errata/RHSA-2017:1677
http://www.securitytracker.com/id/1038476