From 968a3d01fa79f055f93a1c3ed1535ecbcbdbb842 Mon Sep 17 00:00:00 2001 From: Florian Apolloner Date: Mon, 27 Dec 2021 14:48:03 +0100 Subject: Fixed CVE-2021-45115 -- Prevented DoS vector in UserAttributeSimilarityValidator. Thanks Chris Bailey for the report. Co-authored-by: Adam Johnson --- docs/topics/auth/passwords.txt | 14 ++++++++++---- 1 file changed, 10 insertions(+), 4 deletions(-) (limited to 'docs/topics') diff --git a/docs/topics/auth/passwords.txt b/docs/topics/auth/passwords.txt index a4154095fc..24ee2d5360 100644 --- a/docs/topics/auth/passwords.txt +++ b/docs/topics/auth/passwords.txt @@ -607,10 +607,16 @@ Django includes four validators: is used: ``'username', 'first_name', 'last_name', 'email'``. Attributes that don't exist are ignored. - The minimum similarity of a rejected password can be set on a scale of 0 to - 1 with the ``max_similarity`` parameter. A setting of 0 rejects all - passwords, whereas a setting of 1 rejects only passwords that are identical - to an attribute's value. + The maximum allowed similarity of passwords can be set on a scale of 0.1 + to 1.0 with the ``max_similarity`` parameter. This is compared to the + result of :meth:`difflib.SequenceMatcher.quick_ratio`. A value of 0.1 + rejects passwords unless they are substantially different from the + ``user_attributes``, whereas a value of 1.0 rejects only passwords that are + identical to an attribute's value. + + .. versionchanged:: 2.2.26 + + The ``max_similarity`` parameter was limited to a minimum value of 0.1. .. class:: CommonPasswordValidator(password_list_path=DEFAULT_PASSWORD_LIST_PATH) -- cgit v1.3