Django before 1.4.21, 1.5.x through 1.6.x, 1.7.x before 1.7.9, and 1.8.x before 1.8.3 uses an incorrect regular expression, which allows remote attackers to inject arbitrary headers and conduct HTTP response splitting attacks via a newline character in an (1) email message to the EmailValidator, a (2) URL to the URLValidator, or unspecified vectors to the (3) validate_ipv4_address or (4) validate_slug validator.

The session backends in Django before 1.4.21, 1.5.x through 1.6.x, 1.7.x before 1.7.9, and 1.8.x before 1.8.3 allows remote attackers to cause a denial of service (session store consumption) via multiple requests with unique session keys.

validators.URLValidator in Django 1.8.x before 1.8.3 allows remote attackers to cause a denial of service (CPU consumption) via unspecified vectors.

The session.flush function in the cached_db backend in Django 1.8.x before 1.8.2 does not properly flush the session, which allows remote attackers to hijack user sessions via an empty string in the session key.