CVE-2017-12154: High severity Linux Linux kernel vulnerability
Last updated 4 July 2026
Other sources
Linux kernel built with the KVM virtualisation support(CONFIGKVM), with nested virtualisation(nVMX) feature enabled(nested=1), is vulnerable to a crash due to disabled external interrupts. As L2 guest could access(r/w) hardware CR8 register of the host(L0).
In a nested virtualisation setup, L2 guest user could use this flaw to potentially crash the host(L0) resulting in DoS.
Upstream patch -------------- -> https://git.kernel.org/linus/51aa68e7d57e3217192d88ce90fd5b8ef29ec94f
Reference: ---------- -> http://www.openwall.com/lists/oss-security/2017/09/26/3
— Red Hat
The preparevmcs02 function in arch/x86/kvm/vmx.c in the Linux kernel through 4.13.3 does not ensure that the "CR8-load exiting" and "CR8-store exiting" L0 vmcs02 controls exist in cases where L1 omits the "use TPR shadow" vmcs12 control, which allows KVM L2 guest OS users to obtain read and write access to the hardware CR8 register.
— Launchpad
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade
debian/linuxto a version that resolves this vulnerability.Fixed in 6.1.176-1Fixed in 6.1.187-1Fixed in 6.12.107-1Fixed in 7.1.13-1 - Upgrade
Upgrade
Linux kernel (KVM nested virtualization / nVMX)to a version that resolves this vulnerability.Patch 51aa68e7d57e3217192d88ce90fd5b8ef29ec94f
Event History
Frequently Asked Questions
What is the severity of CVE-2017-12154?
CVE-2017-12154 has a high severity rating due to the potential for a crash in the KVM nested virtualization environment.
How do I fix CVE-2017-12154?
To fix CVE-2017-12154, update your Linux kernel to a version that is 5.10.223-1 or higher, or 6.1.119-1 or higher.
Which Linux kernel versions are vulnerable to CVE-2017-12154?
Linux kernel versions up to and including 4.13.3 are vulnerable to CVE-2017-12154.
What impact does CVE-2017-12154 have on KVM users?
CVE-2017-12154 can allow an L2 guest to crash the host by manipulating hardware CR8 register access due to disabled external interrupts.
Is nested virtualization in KVM safe after applying the fix for CVE-2017-12154?
Yes, applying the fix will mitigate the specific vulnerability in nested virtualization, enhancing its safety.