The host is installed with PostgreSQL 11.x before 11.21, 12.x before 12.16, 13.x before 13.12 or 14.x before 14.9, or 15.x before 15.4 and is prone to a SQL injection vulnerability. A flaw is present in the application which fails to properly handle an extension script, if it uses @extowner@, @extschema@, or @extschema:...@ inside a quoting construct. Successful exploitation allows an attacker having database-level CREATE privilege to execute arbitrary code as the bootstrap superuser.