Django before 1.4.18, 1.6.x before 1.6.10, and 1.7.x before 1.7.3 allows remote attackers to spoof WSGI headers by using an _ (underscore) character instead of a - (dash) character in an HTTP header, as demonstrated by an X-Auth_User header.
"https://github.com/pypa/advisory-database/blob/main/vulns/django/PYSEC-2015-4.yaml"