Critical Oracle Database flaw needs to be patched. The patch is in the July 2018 CPU patch.
The exploit is in the Oracle Java VM. Read: https://nvd.nist.gov/vuln/detail/CVE-2018-3110
This is an easily exploited flaw, that allows a user with low level privileges ( connect with network access via Oracle Net) can completely hijack the Oracle database.
Affected versions 11.2.0.4, 12.1.0.2, 12.2.0.1, 18
Patch Information: http://www.oracle.com/technetwork/security-advisory/cpujul2018-4258247.html