The to_char function in PostgreSQL before 9.0.19, 9.1.x before 9.1.15, 9.2.x before 9.2.10, 9.3.x before 9.3.6, and 9.4.x before 9.4.1 allows remote authenticated users to cause a denial of service (crash) or possibly execute arbitrary code via a (1) large number of digits when processing a numeric formatting template, which triggers a buffer over-read, or (2) crafted timestamp formatting template, which triggers a buffer overflow.