NULL Pointer Dereference Affecting kernel-rt-kvm package, versions *


Severity

Recommended
0.0
medium
0
10

Based on CentOS security rating.

Threat Intelligence

EPSS
0.05% (18th percentile)

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  • Snyk IDSNYK-CENTOS7-KERNELRTKVM-6327393
  • published29 Feb 2024
  • disclosed28 Feb 2024

Introduced: 28 Feb 2024

CVE-2021-47008  (opens in a new tab)
CWE-476  (opens in a new tab)

How to fix?

There is no fixed version for Centos:7 kernel-rt-kvm.

NVD Description

Note: Versions mentioned in the description apply only to the upstream kernel-rt-kvm package and not the kernel-rt-kvm package as distributed by Centos. See How to fix? for Centos:7 relevant fixed versions and status.

In the Linux kernel, the following vulnerability has been resolved:

KVM: SVM: Make sure GHCB is mapped before updating

Access to the GHCB is mainly in the VMGEXIT path and it is known that the GHCB will be mapped. But there are two paths where it is possible the GHCB might not be mapped.

The sev_vcpu_deliver_sipi_vector() routine will update the GHCB to inform the caller of the AP Reset Hold NAE event that a SIPI has been delivered. However, if a SIPI is performed without a corresponding AP Reset Hold, then the GHCB might not be mapped (depending on the previous VMEXIT), which will result in a NULL pointer dereference.

The svm_complete_emulated_msr() routine will update the GHCB to inform the caller of a RDMSR/WRMSR operation about any errors. While it is likely that the GHCB will be mapped in this situation, add a safe guard in this path to be certain a NULL pointer dereference is not encountered.

CVSS Scores

version 3.1