Date::Manip versions through 6.99 for Perl return corrupted dates via non-ASCII decimal digits that pass the numeric range tests in check. The parse regexes capture year, month and day with the "\d" shorthand, which on a character string matches the whole Unicode decimal digit property "\p{Nd}" and not just "[0-9]". Date::Manip::Base::check then validates the captured fields with numeric comparisons alone ("$y<1 || $y>9999", "$m<1 || $m>12", "$d<1 || $d>$days"), and _parse_check stores the numified fields ("$y+0"). Perl truncates a string at the first character that is not an ASCII digit, so a field whose leading characters are ASCII digits numifies to an in-range prefix and satisfies every test: a year field of three ASCII digits followed by U+0664 ARABIC-INDIC DIGIT FOUR numifies to 202, giving the year 0202, and one non-ASCII digit in the month or day field shifts those fields the same way. The hour, minute and second fields match explicit ASCII character classes ("0?[0-9]", "[0-5][0-9]") and do not shift, though a non-ASCII digit in a fractional hour or minute field truncates the fraction. Any caller that passes an untrusted character string to ParseDate() or Date::Manip::Date->parse() can get back a date that differs from the string it parsed, with no parse error. Where the parsed date gates logic such as an expiry check or a retention window, the shift goes unnoticed.