CVE-2021-46977: linux kernel — Fix

Description

In the Linux kernel, the following vulnerability has been resolved: KVM: VMX: Disable preemption when probing user return MSRs Disable preemption when probing a user return MSR via RDSMR/WRMSR. If the MSR holds a different value per logical CPU, the WRMSR could corrupt the host's value if KVM is preempted between the RDMSR and WRMSR, and then rescheduled on a different CPU. Opportunistically land the helper in common x86, SVM will use the helper in a future commit.

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CVSS v3.1 Score

5.5

MEDIUM

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Affected Products

Vendor	Product	Versions
linux	linux_kernel	5.5 — 5.10.38
linux	linux_kernel	5.11 — 5.11.22
linux	linux_kernel	5.12 — 5.12.5
linux	linux_kernel	All

References

Advisories & Patches

https://git.kernel.org/stable/c/31f29749ee970c251b3a7e5b914108425940d089 https://git.kernel.org/stable/c/5104d7ffcf24749939bea7fdb5378d186473f890 https://git.kernel.org/stable/c/5adcdeb57007ccf8ab7ac20bf787ffb6fafb1a94 https://git.kernel.org/stable/c/e3ea1895df719c4ef87862501bb10d95f4177bed https://git.kernel.org/stable/c/31f29749ee970c251b3a7e5b914108425940d089 https://git.kernel.org/stable/c/5104d7ffcf24749939bea7fdb5378d186473f890 https://git.kernel.org/stable/c/5adcdeb57007ccf8ab7ac20bf787ffb6fafb1a94 https://git.kernel.org/stable/c/e3ea1895df719c4ef87862501bb10d95f4177bed

Frequently Asked Questions

What is CVE-2021-46977? +

In the Linux kernel, the following vulnerability has been resolved: KVM: VMX: Disable preemption when probing user return MSRs Disable preemption when probing a user return MSR via RDSMR/WRMSR. If the MSR holds a different value per logical CPU, the WRMSR could corrupt the host's value if KVM is preempted between the RDMSR and WRMSR, and then rescheduled on a different CPU. Opportunistically land the helper in common x86, SVM will use the helper in a future commit. It has a CVSS v3.1 base score of 5.5 (MEDIUM).

How severe is CVE-2021-46977? +

CVE-2021-46977 has a CVSS v3.1 score of 5.5 out of 10, rated MEDIUM. This is a medium-severity vulnerability that should be remediated as part of regular maintenance.

What products are affected by CVE-2021-46977? +

CVE-2021-46977 affects products from linux, specifically: linux_kernel. Check the affected products table above for specific version ranges.

How do I check if I'm vulnerable to CVE-2021-46977? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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CVE-2021-46977