Upstream information

CVE-2021-32618 at MITRE

Description

The Python "Flask-Security-Too" package is used for adding security features to your Flask application. It is an is an independently maintained version of Flask-Security based on the 3.0.0 version of Flask-Security. All versions of Flask-Security-Too allow redirects after many successful views (e.g. /login) by honoring the ?next query param. There is code in FS to validate that the url specified in the next parameter is either relative OR has the same netloc (network location) as the requesting URL. This check utilizes Pythons urlsplit library. However many browsers are very lenient on the kind of URL they accept and 'fill in the blanks' when presented with a possibly incomplete URL. As a concrete example - setting http://login?next=\\\github.com will pass FS's relative URL check however many browsers will gladly convert this to http://github.com. Thus an attacker could send such a link to an unwitting user, using a legitimate site and have it redirect to whatever site they want. This is considered a low severity due to the fact that if Werkzeug is used (which is very common with Flask applications) as the WSGI layer, it by default ALWAYS ensures that the Location header is absolute - thus making this attack vector mute. It is possible for application writers to modify this default behavior by setting the 'autocorrect_location_header=False`.

SUSE information

Overall state of this security issue: Pending

This issue is currently rated as having moderate severity.

CVSS v2 Scores
  National Vulnerability Database
Base Score 5.8
Vector AV:N/AC:M/Au:N/C:P/I:P/A:N
Access Vector Network
Access Complexity Medium
Authentication None
Confidentiality Impact Partial
Integrity Impact Partial
Availability Impact None
CVSS v3 Scores
  National Vulnerability Database SUSE
Base Score 6.1 6.1
Vector CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
Access Vector Network Network
Access Complexity Low Low
Privileges Required None None
User Interaction Required Required
Scope Changed Changed
Confidentiality Impact Low Low
Integrity Impact Low Low
Availability Impact None None
CVSSv3 Version 3.1 3.1
SUSE Bugzilla entry: 1186190 [NEW]

No SUSE Security Announcements cross referenced.


Status of this issue by product and package

Please note that this evaluation state might be work in progress, incomplete or outdated. Also information for service packs in the LTSS phase is only included for issues meeting the LTSS criteria. If in doubt, feel free to contact us for clarification.

Product(s) Source package State
SUSE Linux Enterprise Module for Basesystem 15 SP2 python-Flask-Security-Too Affected