CVE-2019-10208: SQL Injection

A flaw was discovered in postgresql where arbitrary SQL statements can be executed given a suitable SECURITY DEFINER function. An attacker, with EXECUTE permission on the function, can execute arbitrary SQL as the owner of the function.

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 pgtemp 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, though this vulnerability affects functions observing them and functions not observing them:

References:

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

— Red Hat