Security researcher Alex Verstak reported that <meta name="referrer"> is ignored when a link is opened through the context menu or a middle-click by mouse. This means that, in some situations, the referrer policy is ignored when opening links in new tabs and may cause some pages to open without an HTTP Referer header being set according to the author's intended policy. External Reference: http://www.mozilla.org/security/announce/2015/mfsa2015-49.html Acknowledgements: Red Hat would like to thank the Mozilla project for reporting this issue. Upstream acknowledges Alex Verstak as the original reporter. Statement: This issue does not affect the version of firefox and thunderbird as shipped with Red Hat Enterprise Linux 5, 6 and 7.