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AUSCERT External Security Bulletin Redistribution
Django releases important security updates
19 December 2019
AusCERT Security Bulletin Summary
Operating System: Windows
UNIX variants (UNIX, Linux, OSX)
Impact/Access: Unauthorised Access -- Remote/Unauthenticated
CVE Names: CVE-2019-19844
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Django security releases issued: 3.0.1, 2.2.9, and 1.11.27
Posted by Carlton Gibson, Mariusz Felisiak, James Bennett on December 18, 2019
In accordance with our security release policy, the Django team is issuing
Django 3.0.1, Django 2.2.9 and Django 1.11.27. These releases address the
security issue detailed below. We encourage all users of Django to upgrade as
soon as possible.
These releases are also issued outside of our normal bugfix/release schedule,
and did not have the usual one-week prenotification period. By the time the
Django security team was made aware of this security issue, its mechanics were
already public knowledge, and it was judged best to issue new releases of
CVE-2019-19844: Potential account hijack via password reset form
Django's password-reset form uses a case-insensitive query to retrieve accounts
matching the email address requesting the password reset. Because this
typically involves explicit or implicit case transformations, an attacker who
knows the email address associated with a user account can craft an email
address which is distinct from the address associated with that account, but
which -- due to the behavior of Unicode case transformations -- ceases to be
distinct after case transformation, or which will otherwise compare equal given
database case-transformation or collation behavior. In such a situation, the
attacker can receive a valid password-reset token for the user account.
To resolve this, two changes were made in Django:
1. After retrieving a list of potentially-matching accounts from the database,
Django's password reset functionality now also checks the email address for
equivalence in Python, using the recommended identifier-comparison process
from Unicode Technical Report 36, section 2.11.2(B)(2).
2. When generating password-reset emails, Django now sends to the email
address retrieved from the database, rather than the email address
submitted in the password-reset request form.
This issue was brought to the attention of the Django security team by Simon
Charette, who became aware of it after reading a public disclosure of a similar
issue which affected GitHub.
Affected supported versions
* Django master branch
* Django 3.0
* Django 2.2
* Django 1.11
Patches to resolve the issue have been applied to Django's master branch and
the 3.0, 2.2, and 1.11 release branches. The patches may be obtained from the
* On the master branch
* On the 3.0 release branch
* On the 2.2 release branch
* On the 1.11 release branch
The following releases have been issued:
* Django 3.0.1 (download Django 3.0.1 | 3.0.1 checksums)
* Django 2.2.9 (download Django 2.2.9 | 2.2.9 checksums)
* Django 1.11.27 (download Django 1.11.27 | 1.11.27 checksums)
The PGP key ID used for these releases is Mariusz Felisiak: 2EF56372BA48CD1B.
General notes regarding security reporting
As always, we ask that potential security issues be reported via private email
to email@example.com, and not via Django's Trac instance or the
django-developers list. Please see our security policies for further
As noted above, because the underlying cause of this issue was already publicly
known, these releases were issued without the usual prenotification process.
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