# Django 2.1.8.dev20190330215650 documentation

# Django 1.5.5 release notes

October 23, 2013

Django 1.5.5 fixes a couple security-related bugs and several other bugs in the 1.5 series.

## Readdressed denial-of-service via password hashers

Django 1.5.4 imposes a 4096-byte limit on passwords in order to mitigate a denial-of-service attack through submission of bogus but extremely large passwords. In Django 1.5.5, we've reverted this change and instead improved the speed of our PBKDF2 algorithm by not rehashing the key on every iteration.

## Properly rotate CSRF token on login

This behavior introduced as a security hardening measure in Django 1.5.2 did not work properly and is now fixed.

## Bugfixes

- Fixed a data corruption bug with `datetime_safe.datetime.combine` (#21256).
- Fixed a Python 3 incompatibility in `django.utils.text.unescape_entities()` (#21185).
- Fixed a couple data corruption issues with `QuerySet` edge cases under Oracle and MySQL (#21203, #21126).
- Fixed crashes when using combinations of `annotate()`, `select_related()`, and `only()` (#16436).

## Backwards incompatible changes

- The undocumented `django.core.servers.basehttp.WSGIServerException` has been removed. Use `socket.error` provided by the standard library instead.