The Linux kernel before 2.6.16.9 and the FreeBSD kernel, when running on AMD64 and other 7th and 8th generation AuthenticAMD processors, only save/restore the FOP, FIP, and FDP x87 registers in FXSAVE/FXRSTOR when an exception is pending, which allows one process to determine portions of the state of floating point instructions of other processes, which can be leveraged to obtain sensitive information such as cryptographic keys. NOTE: this is the documented behavior of AMD64 processors, but it is inconsistent with Intel processors in a security-relevant fashion that was not addressed by the kernels.
ftp://ftp.freebsd.org/pub/FreeBSD/CERT/advisories/FreeBSD-SA-06:14.fpu.asc
http://kb.vmware.com/kb/2533126
http://kernel.org/pub/linux/kernel/v2.6/ChangeLog-2.6.16.9
http://lists.opensuse.org/opensuse-security-announce/2014-03/msg00021.html
http://marc.info/?l=linux-kernel&m=114548768214478&w=2
https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=187910
https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=187911
http://secunia.com/advisories/19715
http://secunia.com/advisories/19724
http://secunia.com/advisories/19735
http://secunia.com/advisories/20398
http://secunia.com/advisories/20671
http://secunia.com/advisories/20716
http://secunia.com/advisories/20914
http://secunia.com/advisories/21035
http://secunia.com/advisories/21136
http://secunia.com/advisories/21465
http://secunia.com/advisories/21983
http://secunia.com/advisories/22417
http://secunia.com/advisories/22875
http://secunia.com/advisories/22876
http://security.freebsd.org/advisories/FreeBSD-SA-06:14-amd.txt
http://securitytracker.com/id?1015966
https://exchange.xforce.ibmcloud.com/vulnerabilities/25871
https://oval.cisecurity.org/repository/search/definition/oval%3Aorg.mitre.oval%3Adef%3A9995
http://support.avaya.com/elmodocs2/security/ASA-2006-180.htm
http://support.avaya.com/elmodocs2/security/ASA-2006-200.htm
http://www.debian.org/security/2006/dsa-1097
http://www.debian.org/security/2006/dsa-1103
http://www.novell.com/linux/security/advisories/2006-05-31.html
http://www.redhat.com/support/errata/RHSA-2006-0437.html
http://www.redhat.com/support/errata/RHSA-2006-0575.html
http://www.redhat.com/support/errata/RHSA-2006-0579.html
http://www.ubuntu.com/usn/usn-302-1
http://www.vmware.com/download/esx/esx-213-200610-patch.html
http://www.vmware.com/download/esx/esx-254-200610-patch.html
http://www.vupen.com/english/advisories/2006/1426
http://www.vupen.com/english/advisories/2006/1475
http://www.vupen.com/english/advisories/2006/2554