A flaw was found in the way Postgresql allowed a user to modify the behavior of a query for other users. An attacker with a user account could use this flaw to execute code with the permissions of superuser in the database (CVE-2018-1058).
Postgresql 9.6.x before 9.6.9 is vulnerable in the adminpack extension, the pgcatalog.pglogfilerotate() function doesn't follow the same ACLs than pgrorate_logfile. If the adminpack is added to a database, an attacker able to connect to it could exploit this to force log rotation (CVE-2018-1115).
Andrew Krasichkov discovered that libpq did not reset all its connection state during reconnects (CVE-2018-10915).
It was discovered that some "CREATE TABLE" statements could disclose server memory (CVE-2018-10925).
Fully fixing these security issues requires manual intervention. See the upstream advisories for details.