CVE-2012-1961
Mozilla Firefox 4.x through 13.0, Firefox ESR 10.x before 10.0.6, Thunderbird 5.0 through 13.0, Thunderbird ESR 10.x before 10.0.6, and SeaMonkey before 2.11 do not properly handle duplicate values in X-Frame-Options headers, which makes it easier for remote attackers to conduct clickjacking attacks via a FRAME element referencing a web site that produces these duplicate values.
Date published : 2012-07-18
http://www.securityfocus.com/bid/54584
http://www.mozilla.org/security/announce/2012/mfsa2012-51.html