The contributed HSTS module makes it easy for site administrators to implement HTTP Strict Transport Security (HSTS) by setting the Strict-Transport-Security header on each page generated by Drupal.

HSTS module provides a configuration UI for the HSTS "include subdomains" directive, which indicates that the browser should apply the HSTS policy to all subdomains on the site's domain.

HSTS module did not implement the "include subdomains" directive correctly (it is misspelled as include_subdomains rather than includeSubDomains). As a result, the HSTS policy was not applied to subdomains as site administrators had expected.

This vulnerability is mitigated by the fact that only subdomains where HSTS was expected to be enabled are affected and an attacker would still need to execute a man-in-the-middle attack to exploit the issue.

CVE identifier(s) issued

  • CVE-2015-5505

Versions affected

  • HSTS 7.x-1.x versions prior to 7.x-1.2.
  • HSTS 6.x-1.x versions prior to 6.x-1.1.

Drupal core is not affected. If you do not use the contributed HTTP Strict Transport Security module, there is nothing you need to do.


Install the latest version:

  • If you use the HSTS module for Drupal 7.x, upgrade to HSTS 7.x-1.2
  • If you use the HSTS module for Drupal 6.x, upgrade to HSTS 6.x-1.1

Also see the HTTP Strict Transport Security project page.

Reported by

Fixed by

Coordinated by

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