Drupal 8.3.4 and Drupal 7.56 are maintenance releases which contain fixes for security vulnerabilities.
Updating your existing Drupal 8 and 7 sites is strongly recommended (see instructions for Drupal 8 and for Drupal 7). This release fixes security issues only; there are no new features nor non-security-related bug fixes in this release. See the 8.3.4 release notes and the 7.56 release notes for details on important changes and known issues affecting this release. Read on for details of the security vulnerabilities that were fixed in this release.
Advisory ID: DRUPAL-SA-CORE-2017-003
Project: Drupal core
Version: 7.x, 8.x
Date: 2017-June-21
Multiple vulnerabilities
Description
PECL YAML parser unsafe object handling - Critical - Drupal 8 - CVE-2017-6920
PECL YAML parser does not handle PHP objects safely during certain operations within Drupal core. This could lead to remote code execution.
File REST resource does not properly validate - Less Critical - Drupal 8 - CVE-2017-6921
The file REST resource does not properly validate some fields when manipulating files. A site is only affected by this if the site has the RESTful Web Services (rest) module enabled, the file REST resource is enabled and allows PATCH requests, and an attacker can get or register a user account on the site with permissions to upload files and to modify the file resource.
Files uploaded by anonymous users into a private file system can be accessed by other anonymous users - Moderately Critical - Drupal 7 and Drupal 8 - CVE-2017-6922
Private files that have been uploaded by an anonymous user but not permanently attached to content on the site should only be visible to the anonymous user that uploaded them, rather than all anonymous users. Drupal core did not previously provide this protection, allowing an access bypass vulnerability to occur. This issue is mitigated by the fact that in order to be affected, the site must allow anonymous users to upload files into a private file system.
The security team has also received reports that this vulnerability is being exploited for spam purposes, similar to the scenario discussed in PSA-2016-003 for the public file system.
Versions affected
Drupal core 7.x versions prior to 7.56
Drupal core 8.x versions prior to 8.3.4
Solution
Install the latest version:
If you use Drupal 7.x, upgrade to Drupal core 7.56
If you use Drupal 8.x, upgrade to Drupal core 8.3.4
Also see the Drupal core project page.
Reported by
PECL YAML parser unsafe object handling
Heine Deelstra of the Drupal Security team
File REST resource does not properly validate
Samuel Mortenson
Files uploaded by anonymous users into a private file system can be accessed by other anonymous users
Greg Knaddison of the Drupal Security team
Mori Sugimoto of the Drupal Security team
iancawthorne
Fixed by
PECL YAML parser unsafe object handling
xjm of the Drupal Security team
Alex Pott of the Drupal Security team
Peter Wolanin of the Drupal Security team
File REST resource does not properly validate
Samuel Mortenson
Wim Leers
Alex Pott of the Drupal Security team
xjm of the Drupal Security team
Sascha Grossenbacher
Files uploaded by anonymous users into a private file system can be accessed by other anonymous users
David Rothstein of the Drupal Security team
Peter Wolanin of the Drupal Security team
Michael Hess of the Drupal Security team
xjm of the Drupal Security team
Chris McCafferty of the Drupal Security team
Lee Rowlands of the Drupal Security team
Alex Pott of the Drupal Security team
Nathaniel Catchpole of the Drupal Security team
Stefan Ruijsenaars of the Drupal Security team
Nate Haug
Gareth Goodwin
Contact and More Information
The Drupal security team can be reached at security at drupal.org or via the contact form at https://www.drupal.org/contact.
Learn more about the Drupal Security team and their policies, writing secure code for Drupal, and securing your site.
Follow the Drupal Security Team on Twitter at https://twitter.com/drupalsecurity
