Debian 8: DLA-1874-1 Critical: PostgreSQL Arbitrary SQL Execution

Given a suitable `SECURITY DEFINER` function, an attacker can execute
arbitrary SQL under the identity of the function owner. An attack
requires `EXECUTE` permission on the function, which must itself contain
a function call having inexact argument type match. For example,
`length('foo'::varchar)` and `length('foo')` are inexact, while
`length('foo'::text)` is exact. As part of exploiting this
vulnerability, the attacker uses `CREATE DOMAIN` to create a type in a
`pg_temp` schema. The attack pattern and fix are similar to that for
CVE-2007-2138.

Writing `SECURITY DEFINER` functions continues to require following the
considerations noted in the documentation:

https://www.postgresql.org/docs/devel/sql-createfunction.html#SQL-CREATEFUNCTION-SECURITY

The PostgreSQL project thanks Tom Lane for reporting this problem.

For Debian 8 "Jessie", this problem has been fixed in version
9.4.24-0+deb8u1.

We recommend that you upgrade your postgresql-9.4 packages.