In PHP before 5.6.31, 7.x before 7.0.21, and 7.1.x before 7.1.7, lack of a bounds check in the date extension’s timelib_meridian parsing code could be used by attackers able to supply date strings to leak information from the interpreter, related to an ext/date/lib/parse_date.c out-of-bounds read affecting the php_parse_date function.