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.

The Unity Linux 20 host has a package installed that is affected by a vulnerability as referenced in the UTSA-2026-013287 advisory.

    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.

Tenable has extracted the preceding description block directly from the Unity Linux security advisory.

Note that Nessus has not tested for this issue but has instead relied only on the application's self-reported version number.

The Linux/Unix host has one or more packages installed that are impacted by a vulnerability without a vendor supplied patch available.

  - 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.
    (CVE-2021-47008)

Note that Nessus relies on the presence of the package as reported by the vendor.

ID	Name	Product	Family	Severity
307949	Unity Linux 20.1070e Security Update: kernel (UTSA-2026-013287)	Nessus	Unity Linux Local Security Checks	medium
243610	Linux Distros Unpatched Vulnerability : CVE-2021-47008	Nessus	Misc.	medium
239060	TencentOS Server 4: kernel (TSSA-2024:0958)	Nessus	Tencent Local Security Checks	high

Detections

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CVE-2021-47008

medium

Tenable Plugins

medium

medium

high