Debian LTS: DLA-1872-1 Moderate: python-django Denial-Of-Service Risk

If django.utils.text.Truncator's chars() and words() methods were
passed the html=True argument, they were extremely slow to
evaluate certain inputs due to a catastrophic backtracking
vulnerability in a regular expression. The chars() and words()
methods are used to implement the truncatechars_html and
truncatewords_html template filters, which were thus vulnerable.

The regular expressions used by Truncator have been simplified in
order to avoid potential backtracking issues. As a consequence,
trailing punctuation may now at times be included in the
truncated output.

* CVE-2019-14233: Prevent a possible denial-of-service in strip_tags().

Due to the behavior of the underlying HTMLParser,
django.utils.html.strip_tags() would be extremely slow to
evaluate certain inputs containing large sequences of nested
incomplete HTML entities. The strip_tags() method is used to
implement the corresponding striptags template filter, which was