Debian Security Advisory
DLA-1872-1 python-django -- LTS security update
- Date Reported:
- 06 Aug 2019
- Affected Packages:
- Security database references:
- In Mitre's CVE dictionary: CVE-2019-14232, CVE-2019-14233.
- More information:
It was discovered that there were two vulnerabilities in the Django web development framework:
Prevent a possible denial-of-service in django.utils.text.Truncator.
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.
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 thus also vulnerable.
strip_tags() now avoids recursive calls to HTMLParser when progress removing tags, but necessarily incomplete HTML entities, stops being made.
Remember that absolutely NO guarantee is provided about the results of strip_tags() being HTML safe. So NEVER mark safe the result of a strip_tags() call without escaping it first, for example with django.utils.html.escape().
For Debian 8
Jessie, these problems have been fixed in version 1.7.11-1+deb8u7.
We recommend that you upgrade your python-django packages.
Further information about Debian LTS security advisories, how to apply these updates to your system and frequently asked questions can be found at: https://wiki.debian.org/LTS