postgresql is vulnerable to denial of service (DoS) attacks. The vulnerability exists as PostgreSQL before 9.1.20, 9.2.x before 9.2.15, 9.3.x before 9.3.11, 9.4.x before 9.4.6, and 9.5.x before 9.5.1 allows remote attackers to cause a denial of service (infinite loop or buffer overflow and crash) via a large Unicode character range in a regular expression.