An issue was discovered in Django 2.0 before 2.0.3, 1.11 before 1.11.11, and 1.8 before 1.8.19. The django.utils.html.urlize() function was extremely slow to evaluate certain inputs due to catastrophic backtracking vulnerabilities in two regular expressions (only one regular expression for Django 1.8.x). The urlize() function is used to implement the urlize and urlizetrunc template filters, which were thus vulnerable.

Affected: Ubuntu:14.04:LTS: python-django, Ubuntu:16.04:LTS: python-django

James Davis discovered that Django incorrectly handled certain template filters. A remote attacker could possibly use this issue to cause Django to consume resources, resulting in a denial of service.