src/cve/2021-38295.rst

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.. _cve/2021-38295:

===========================================================
CVE-2021-38295: Apache CouchDB Privilege Escalation
===========================================================

:Date: 12.10.2021

:Affected: 3.1.1 and below

:Severity: Low

:Vendor: The Apache Software Foundation

Description
===========

A malicious user with permission to create documents in a database is able
to attach a HTML attachment to a document. If a CouchDB admin opens that
attachment in a browser, e.g. via the CouchDB admin interface Fauxton,
any JavaScript code embedded in that HTML attachment will be executed within
the security context of that admin. A similar route is available with the
already deprecated `_show` and `_list` functionality.

This *privilege escalation* vulnerability allows an attacker to add or remove
data in any database or make configuration changes.

Mitigation
==========

CouchDB :ref:`3.2.0 <release/3.2.0>`  and onwards adds `Content-Security-Policy`
headers for all attachment, `_show` and `_list` requests. This breaks certain
niche use-cases and there are configuration options to restore the previous
behaviour for those who need it.

CouchDB :ref:`3.1.2 <release/3.1.2>`  defaults to the previous behaviour, but
adds configuration options to turn `Content-Security-Policy` headers on for
all affected requests.

Credit
======

This issue was identified by `Cory Sabol`_ of `Secure Ideas`_.

.. _Secure Ideas: https://secureideas.com/
.. _Cory Sabol: mailto:cory@secureideas.com