The Public Key Pinning (PKP) implementation in Mozilla Firefox before 33.0 skips pinning checks upon an unspecified issuer-verification error, which makes it easier for remote attackers to bypass an intended pinning configuration and spoof a web site via a crafted certificate that leads to presentation of the Untrusted Connection dialog to the user.
https://security.gentoo.org/glsa/201504-01
https://bugzilla.mozilla.org/show_bug.cgi?id=1066190
http://www.ubuntu.com/usn/USN-2372-1
http://www.securitytracker.com/id/1031028
http://www.securityfocus.com/bid/70434
http://www.oracle.com/technetwork/topics/security/bulletinapr2016-2952098.html
http://www.mozilla.org/security/announce/2014/mfsa2014-80.html
http://secunia.com/advisories/62023
http://secunia.com/advisories/62022
http://lists.opensuse.org/opensuse-updates/2014-11/msg00002.html
http://lists.opensuse.org/opensuse-updates/2014-11/msg00001.html
http://lists.fedoraproject.org/pipermail/package-announce/2014-October/141085.html
http://lists.fedoraproject.org/pipermail/package-announce/2014-November/141796.html