{"id":"CVE-2021-46977","title":"In the Linux kernel, the following vulnerability has been resolved:\n\nKVM: VMX: Disable preemption when probing user return MSRs\n\nDisable preemption when probing a user return MSR via RDSMR/WRMSR","summary":"In the Linux kernel, the following vulnerability has been resolved:\n\nKVM: VMX: Disable preemption when probing user return MSRs\n\nDisable preemption when probing a user return MSR via RDSMR/WRMSR.  If\nthe MSR holds a different value per l…","severity":"high","cvss":7.8,"cvssVector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","vendor":"linux","product":"linux_kernel","affected":["linux_kernel >= 5.5, < 5.10.38","linux_kernel >= 5.11, < 5.11.22","linux_kernel >= 5.12, < 5.12.5","linux_kernel = 5.13"],"patched":["linux_kernel 5.12.5"],"published":"2024-02-28","updated":"2026-08-04","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2021-46977","references":[{"url":"https://git.kernel.org/stable/c/31f29749ee970c251b3a7e5b914108425940d089","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/5104d7ffcf24749939bea7fdb5378d186473f890","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/5adcdeb57007ccf8ab7ac20bf787ffb6fafb1a94","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/e3ea1895df719c4ef87862501bb10d95f4177bed","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/31f29749ee970c251b3a7e5b914108425940d089","label":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://git.kernel.org/stable/c/5104d7ffcf24749939bea7fdb5378d186473f890","label":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://git.kernel.org/stable/c/5adcdeb57007ccf8ab7ac20bf787ffb6fafb1a94","label":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://git.kernel.org/stable/c/e3ea1895df719c4ef87862501bb10d95f4177bed","label":"af854a3a-2127-422b-91ae-364da2661108"}],"tags":["nvd"],"epss":0.00241,"epssPercentile":0.13552,"ingestedAt":"2026-08-04T10:39:38.792Z","slug":"CVE-2021-46977","body":"## Overview\n\nIn the Linux kernel, the following vulnerability has been resolved:\n\nKVM: VMX: Disable preemption when probing user return MSRs\n\nDisable preemption when probing a user return MSR via RDSMR/WRMSR.  If\nthe MSR holds a different value per logical CPU, the WRMSR could corrupt\nthe host's value if KVM is preempted between the RDMSR and WRMSR, and\nthen rescheduled on a different CPU.\n\nOpportunistically land the helper in common x86, SVM will use the helper\nin a future commit.\n\n## Affected\n\n- `linux_kernel >= 5.5, < 5.10.38`\n- `linux_kernel >= 5.11, < 5.11.22`\n- `linux_kernel >= 5.12, < 5.12.5`\n- `linux_kernel = 5.13`\n\n## Remediation\n\nUpgrade past the affected range:\n\n- `linux_kernel 5.12.5`","depth":"twilight","depthScore":43,"depthScoreParts":{"impact":42.9,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[]}