{
  "threat_severity" : "Low",
  "public_date" : "2015-01-27T00:00:00Z",
  "bugzilla" : {
    "description" : "kernel: kvm: insufficient sysenter emulation when invoked from 16-bit code",
    "id" : "1186448",
    "url" : "https://bugzilla.redhat.com/show_bug.cgi?id=1186448"
  },
  "cvss" : {
    "cvss_base_score" : "6.2",
    "cvss_scoring_vector" : "AV:L/AC:H/Au:N/C:C/I:C/A:C",
    "status" : "verified"
  },
  "cwe" : "CWE-391",
  "details" : [ "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.", "It was found that the Linux kernel KVM subsystem's sysenter instruction emulation was not sufficient. An unprivileged guest user could use this flaw to escalate their privileges by tricking the hypervisor to emulate a SYSENTER instruction in 16-bit mode, if the guest OS did not initialize the SYSENTER model-specific registers (MSRs). Note: Certified guest operating systems for Red Hat Enterprise Linux with KVM do initialize the SYSENTER MSRs and are thus not vulnerable to this issue when running on a KVM hypervisor." ],
  "statement" : "This issue did not affect the kvm packages as shipped with Red Hat Enterprise Linux 5 as they lack support for sysenter instruction emulation.\nThis issue affects the Linux kernel packages as shipped with Red Hat Enterprise Linux 7. A future update may address this issue.\nPlease note that the Red Hat Enterprise Linux with KVM certified guest operating\nsystems do initialize the SYSENTER MSRs and are thus not vulnerable to\nthis issue when running on KVM hypervisor.",
  "acknowledgement" : "Red Hat would like to thank Nadav Amit for reporting this issue.",
  "affected_release" : [ {
    "product_name" : "Red Hat Enterprise Linux 6",
    "release_date" : "2015-07-20T00:00:00Z",
    "advisory" : "RHSA-2015:1272",
    "cpe" : "cpe:/o:redhat:enterprise_linux:6",
    "package" : "kernel-0:2.6.32-573.el6"
  }, {
    "product_name" : "Red Hat Enterprise Linux 7",
    "release_date" : "2015-11-19T00:00:00Z",
    "advisory" : "RHSA-2015:2152",
    "cpe" : "cpe:/o:redhat:enterprise_linux:7",
    "package" : "kernel-0:3.10.0-327.el7"
  } ],
  "package_state" : [ {
    "product_name" : "Red Hat Enterprise Linux 5",
    "fix_state" : "Not affected",
    "package_name" : "kvm",
    "cpe" : "cpe:/o:redhat:enterprise_linux:5"
  }, {
    "product_name" : "Red Hat Enterprise Linux 7",
    "fix_state" : "Not affected",
    "package_name" : "kernel-rt",
    "cpe" : "cpe:/o:redhat:enterprise_linux:7"
  }, {
    "product_name" : "Red Hat Enterprise MRG 2",
    "fix_state" : "Not affected",
    "package_name" : "realtime-kernel",
    "cpe" : "cpe:/a:redhat:enterprise_mrg:2"
  } ],
  "references" : [ "https://www.cve.org/CVERecord?id=CVE-2015-0239\nhttps://nvd.nist.gov/vuln/detail/CVE-2015-0239" ],
  "name" : "CVE-2015-0239",
  "csaw" : false
}