CVE-2015-0239

Published: 23 January 2015

The em_sysenter function in arch/x86/kvm/emulate.c in the Linux kernel before 3.18.5, when the guest OS lacks SYSENTER MSR initialization, allows guest OS users to gain guest OS privileges or cause a denial of service (guest OS crash) by triggering use of a 16-bit code segment for emulation of a SYSENTER instruction.

From the Ubuntu security team

A flaw was discovered in the Kernel Virtual Machine's (KVM) emulation of the SYSTENTER instruction when the guest OS does not initialize the SYSENTER MSRs. A guest OS user could exploit this flaw to cause a denial of service of the guest OS (crash) or potentially gain privileges on the guest OS.

Status

Notes

android kernels (flo, goldfish, grouper, maguro, mako and manta) are
not supported on the Ubuntu Touch 14.04 preview kernels
linux-lts-saucy no longer receives official support
linux-lts-quantal no longer receives official support

References

• https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2015-0239
• https://ubuntu.com/security/notices/USN-2513-1
• https://ubuntu.com/security/notices/USN-2514-1
• https://ubuntu.com/security/notices/USN-2515-1
• https://ubuntu.com/security/notices/USN-2516-1
• https://ubuntu.com/security/notices/USN-2517-1
• https://ubuntu.com/security/notices/USN-2518-1
• NVD
• Launchpad
• Debian

Bugs

• https://launchpad.net/bugs/1414651