The remote Debian host is missing a security-related update.
James Davis discovered two issues in Django, a high-level Python web development framework, that can lead to a denial-of-service attack. An attacker with control on the input of the django.utils.html.urlize() function or django.utils.text.Truncator's chars() and words() methods could craft a string that might stuck the execution of the application.
Upgrade the python-django packages. For the oldstable distribution (jessie), these problems have been fixed in version 1.7.11-1+deb8u3. For the stable distribution (stretch), these problems have been fixed in version 1:1.10.7-2+deb9u1.