PT-2024-11086 · Linux · Linux Kernel

Sean Christopherson · Published 2021-05-07 · Updated 2025-01-08 · CVE-2021-46977

Positive Technologies (AI Summary)

CVSS v3.1

5.5

Medium

Base vector

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

Name of the Vulnerable Software and Affected Versions Linux kernel (affected versions not specified)

Description The issue is related to KVM: VMX, where preemption is disabled when probing user return MSRs 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. The helper will be used in common x86, and SVM will use it in a future commit.

Recommendations At the moment, there is no information about a newer version that contains a fix for this vulnerability.

Resource Exhaustion

Weakness Enumeration

CWE-400

Related Identifiers

BDU:2025-03848

CVE-2021-46977

Affected Products

Linux Kernel

References · 22

• https://osv.dev/vulnerability/CVE-2021-46977 · Vendor Advisory
• https://git.kernel.org/stable/c/5104d7ffcf24749939bea7fdb5378d186473f890 · Patch
• https://bdu.fstec.ru/vul/2025-03848 · Security Note
• https://git.kernel.org/stable/c/e3ea1895df719c4ef87862501bb10d95f4177bed · Patch
• https://osv.dev/vulnerability/DEBIAN-CVE-2021-46977 · Vendor Advisory
• https://git.kernel.org/stable/c/31f29749ee970c251b3a7e5b914108425940d089 · Patch
• https://osv.dev/vulnerability/UBUNTU-CVE-2021-46977 · Vendor Advisory
• https://git.kernel.org/stable/c/5adcdeb57007ccf8ab7ac20bf787ffb6fafb1a94 · Patch
• https://security-tracker.debian.org/tracker/CVE-2021-46977 · Vendor Advisory
• https://cve.org/CVERecord?id=CVE-2021-46977 · Security Note
• https://ubuntu.com/security/CVE-2021-46977 · Vendor Advisory
• https://nvd.nist.gov/vuln/detail/CVE-2021-46977 · Security Note
• https://git.linuxtesting.ru/pub/scm/linux/kernel/git/lvc/linux-stable.git/commit/?h=v5.10.176-lvc1&id=31f29749ee970c251b3a7e5b914108425940d089 · Note
• https://git.linuxtesting.ru/pub/scm/linux/kernel/git/lvc/linux-stable.git/commit/?h=v5.10.176-lvc1&id=31f29749ee970c251b3a7e5b914108425940d089 · Note
• https://kernel.org/pub/linux/kernel/v5.x/ChangeLog-5.12.5 · Note