high
7.8
CWE
416
Advisory Published
CVE Published
Updated

CVE-2019-7221: Use After Free

First published: Sat Feb 02 2019(Updated: )

A use after free issue was found in the way Linux kernel's KVM hypervisor emulates a preemption timer for L2 guest when nested(=1) virtualization is enabled. This high resolution timer(hrtimer) runs when L2 guest is active. After VM exit, in sync_vmcs12() timer object is stopped. The use-after-free occurs if the timer object is free'd before calling sync_vmcs12() routine. A guest user/process could use this flaw to crash the host kernel resulting in DoS OR potentially gain privileged access to a system. It affects only Intel processors and only when nested virtualization is enabled. Upstream patch: --------------- -&gt; <a href="https://git.kernel.org/linus/ecec76885bcfe3294685dc363fd1273df0d5d65f">https://git.kernel.org/linus/ecec76885bcfe3294685dc363fd1273df0d5d65f</a> Reference: ---------- -&gt; <a href="https://www.openwall.com/lists/oss-security/2019/02/18/2">https://www.openwall.com/lists/oss-security/2019/02/18/2</a>

Credit: cve@mitre.org cve@mitre.org cve@mitre.org

Affected SoftwareAffected VersionHow to fix
Linux Kernel<=4.20.5
openSUSE=15.0
Fedoraproject Fedora=28
Fedoraproject Fedora=29
Debian GNU/Linux=8.0
Ubuntu Linux=14.04
Ubuntu Linux=16.04
Ubuntu Linux=18.04
Ubuntu Linux=18.10
NetApp Active IQ
NetApp Element Software
redhat openshift container platform=3.11
Red Hat Enterprise Linux=7.0
redhat enterprise Linux desktop=7.0
redhat enterprise Linux server=7.0
redhat enterprise Linux server aus=7.6
redhat enterprise Linux server eus=7.6
redhat enterprise Linux server tus=7.6
redhat enterprise Linux workstation=7.0
debian/linux
5.10.223-1
5.10.226-1
6.1.123-1
6.1.128-1
6.12.12-1
6.12.13-1
Fedora=28
Fedora=29
Debian=8.0
Ubuntu=14.04
Ubuntu=16.04
Ubuntu=18.04
Ubuntu=18.10

Remedy

http://www.openwall.com/lists/oss-security/2019/02/18/2

Remedy

https://bugs.chromium.org/p/project-zero/issues/detail?id=1760

Remedy

https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=ecec76885bcfe3294685dc363fd1273df0d5d65f

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Reference Links

Frequently Asked Questions

  • What is the severity of CVE-2019-7221?

    CVE-2019-7221 has been rated as a high severity vulnerability due to its potential impact on the Linux kernel's KVM hypervisor.

  • How do I fix CVE-2019-7221?

    To resolve CVE-2019-7221, upgrade to a fixed kernel version such as 5.10.223-1 or later.

  • Which software versions are affected by CVE-2019-7221?

    CVE-2019-7221 affects Linux kernel versions up to and including 4.20.5 among various distributions like openSUSE, Fedora, and Ubuntu.

  • What systems are impacted by CVE-2019-7221?

    The systems impacted by CVE-2019-7221 include various Linux distributions and versions that are utilizing the Linux kernel's KVM hypervisor.

  • What is the exploit type of CVE-2019-7221?

    CVE-2019-7221 is classified as a use-after-free vulnerability in the KVM hypervisor.

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