arch/x86/entry/entry_64.S in the Linux kernel before 4.1.6 on the x86_64 platform improperly relies on espfix64 during nested NMI processing, which allows local users to gain privileges by triggering an NMI within a certain instruction window.

References

• https://nvd.nist.gov/vuln/detail/CVE-2015-3290
• torvalds/linux@9b6e6a8
• https://bugzilla.redhat.com/show_bug.cgi?id=1243465
• https://www.exploit-db.com/exploits/37722/
• http://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=9b6e6a8334d56354853f9c255d1395c2ba570e0a
• http://lists.opensuse.org/opensuse-security-announce/2015-08/msg00011.html
• http://www.debian.org/security/2015/dsa-3313
• http://www.kernel.org/pub/linux/kernel/v4.x/ChangeLog-4.1.6
• http://www.openwall.com/lists/oss-security/2015/07/22/7
• http://www.openwall.com/lists/oss-security/2015/08/04/8
• http://www.securityfocus.com/bid/76004
• http://www.ubuntu.com/usn/USN-2687-1
• http://www.ubuntu.com/usn/USN-2688-1
• http://www.ubuntu.com/usn/USN-2689-1
• http://www.ubuntu.com/usn/USN-2690-1
• http://www.ubuntu.com/usn/USN-2691-1