Mozilla Firefox 4.x through 9.0, Thunderbird 5.0 through 9.0, and SeaMonkey before 2.7 do not properly initialize data for image/vnd.microsoft.icon images, which allows remote attackers to obtain potentially sensitive information by reading a PNG image that was created through conversion from an ICO image.
lists.opensuse.org/opensuse-security-announce/2012-02/msg00011.html
secunia.com/advisories/49055
www.mandriva.com/security/advisories?name=MDVSA-2012:013
www.mozilla.org/security/announce/2012/mfsa2012-06.html
bugzilla.mozilla.org/show_bug.cgi?id=710079
exchange.xforce.ibmcloud.com/vulnerabilities/72856
oval.cisecurity.org/repository/search/definition/oval%3Aorg.mitre.oval%3Adef%3A14912