Vulnerability Details : CVE-2021-47008
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.
Vulnerability category: Memory Corruption
Products affected by CVE-2021-47008
- cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
- cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
Exploit prediction scoring system (EPSS) score for CVE-2021-47008
0.04%
Probability of exploitation activity in the next 30 days
EPSS Score History
~ 5 %
Percentile, the proportion of vulnerabilities that are scored at or less
CVSS scores for CVE-2021-47008
Base Score | Base Severity | CVSS Vector | Exploitability Score | Impact Score | Score Source | First Seen |
---|---|---|---|---|---|---|
5.5
|
MEDIUM | CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H |
1.8
|
3.6
|
NIST | 2024-12-09 |
CWE ids for CVE-2021-47008
-
The product dereferences a pointer that it expects to be valid but is NULL.Assigned by: nvd@nist.gov (Primary)
References for CVE-2021-47008
-
https://git.kernel.org/stable/c/a3ba26ecfb569f4aa3f867e80c02aa65f20aadad
KVM: SVM: Make sure GHCB is mapped before updating - kernel/git/stable/linux.git - Linux kernel stable treePatch
-
https://git.kernel.org/stable/c/fd722a57fe0b80133dacae4e1c852ee4212f9b2e
KVM: SVM: Make sure GHCB is mapped before updating - kernel/git/stable/linux.git - Linux kernel stable treePatch
-
https://git.kernel.org/stable/c/fb9e14f4f8217a0980f8da2c8ff70dee058cbe47
KVM: SVM: Make sure GHCB is mapped before updating - kernel/git/stable/linux.git - Linux kernel stable treePatch
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