In Django 2.2 before 2.2.24, 3.x before 3.1.12, and 3.2 before 3.2.4, URLValidator, validateipv4address, and validateipv46address do not prohibit leading zero characters in octal literals. This may allow a bypass of access control that is based on IP addresses. (validateipv4address and validateipv46address are unaffected with Python 3.9.5+..) .