CVE-2017-12172

PostgreSQL 10.x before 10.1, 9.6.x before 9.6.6, 9.5.x before 9.5.10, 9.4.x
before 9.4.15, 9.3.x before 9.3.20, and 9.2.x before 9.2.24 runs under a
non-root operating system account, and database superusers have effective
ability to run arbitrary code under that system account. PostgreSQL
provides a script for starting the database server during system boot.
Packages of PostgreSQL for many operating systems provide their own,
packager-authored startup implementations. Several implementations use a
log file name that the database superuser can replace with a symbolic link.
As root, they open(), chmod() and/or chown() this log file name. This often
suffices for the database superuser to escalate to root privileges when
root starts the server.

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