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`.

The Linux/Unix host has one or more packages installed that are impacted by a vulnerability without a vendor supplied patch available.

  - 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`. (CVE-2021-32618)

Note that Nessus relies on the presence of the package as reported by the vendor.

There are packages installed that are affected by a vulnerability referenced in the following CVE:

  - 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`. (CVE-2021-32618)

ID	Name	Product	Family	Type	Severity
262753	Linux Distros Unpatched Vulnerability : CVE-2021-32618	Nessus	Misc.	Local	medium
411587	SCA: security update for flask-security-too (GHSA-6qmf-fj6m-686c)	Tenable Cloud Security	SCA Checks	Local	medium
411587	SCA: security update for flask-security-too (GHSA-6qmf-fj6m-686c)	Tenable Self-Hosted Container Security	SCA Checks	Local	medium

Detections

Analytics

CVE-2021-32618

low

Tenable Plugins

medium

medium

medium