DOS via regular expression catastrophic backtracking in apop method in pop3libA flaw was found in the way catastrophic backtracking was implemented in python's pop3lib's apop method. An attacker could use this flaw to cause denial of service. DOS via regular expression backtracking in difflib.IS_LINE_JUNK method in difflibA flaw was found in the way catastrophic backtracking was implemented in python's difflib.IS_LINE_JUNK method. An attacker could use this flaw to cause denial of service