The Webform Multiple File Upload module allows users to upload multiple files on a Webform.

The Webform Multifile File Upload module contains a Remote Code Execution (RCE) vulnerability where form inputs will be unserialized and a specially crafted form input may trigger arbitrary code execution depending on the libraries available on a site.

This vulnerability is mitigated by the fact that an attacker must have the ability to submit a Webform with a Multiple File Input field. Further, a site must have an object defined with methods that are invoked at wake/destroy that include code that can be leveraged for malicious purposes. Drupal 7 Core contains one such class which can be used to delete arbitrary files, but contributed or custom classes may include methods that can be leveraged for RCE.

Note: this vulnerability exists in the Webform Multiple File Upload (webform_multifile) module. There is a similarly named module Webform Multiple File (webform_multiple_file) which is not related to this issue.

CVE identifier(s) issued

  • A CVE identifier will be requested, and added upon issuance, in accordance with Drupal Security Team processes.

Versions affected

Webform Multifile 7.x-1.x versions prior to 7.x-1.4

Drupal core is not affected. If you do not use the contributed Webform Multiple File Upload module, there is nothing you need to do.


Install the latest version:

Also see the Webform Multiple File Upload project page.

Reported by

Fixed by

Coordinated by

Contact and More Information

The Drupal security team can be reached at security at or via the contact form at

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