NVD

CVE-2021-47255 Detail

Description

In the Linux kernel, the following vulnerability has been resolved: kvm: LAPIC: Restore guard to prevent illegal APIC register access Per the SDM, "any access that touches bytes 4 through 15 of an APIC register may cause undefined behavior and must not be executed." Worse, such an access in kvm_lapic_reg_read can result in a leak of kernel stack contents. Prior to commit 01402cf81051 ("kvm: LAPIC: write down valid APIC registers"), such an access was explicitly disallowed. Restore the guard that was removed in that commit.

Metrics

NVD enrichment efforts reference publicly available information to associate vector strings. CVSS information contributed by other sources is also displayed.

CVSS 4.0 Severity and Vector Strings:

NIST: NVD

N/A

NVD assessment not yet provided.

CVSS 3.x Severity and Vector Strings:

NIST: NVD

Base Score: 7.1 HIGH

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

CVSS 2.0 Severity and Vector Strings:

National Institute of Standards and Technology

NIST: NVD

Base Score: N/A

NVD assessment not yet provided.

References to Advisories, Solutions, and Tools

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URL	Source(s)	Tag(s)
https://git.kernel.org/stable/c/018685461a5b9a9a70e664ac77aef0d7415a3fd5	CVE, kernel.org	Patch
https://git.kernel.org/stable/c/218bf772bddd221489c38dde6ef8e917131161f6	CVE, kernel.org	Patch
https://git.kernel.org/stable/c/a2aff09807fbe4018c269d3773a629949058b210	CVE, kernel.org	Patch
https://git.kernel.org/stable/c/bf99ea52970caeb4583bdba1192c1f9b53b12c84	CVE, kernel.org	Patch

Weakness Enumeration

CWE-ID	CWE Name	Source
NVD-CWE-Other	Other	NIST

Known Affected Software Configurations Switch to CPE 2.2

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Change History

6 change records found show changes

CVE Modified by kernel.org 6/17/2026 12:17:01 AM

Action

Type

Old Value

New Value

Added

Affected

[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","programFiles":["arch/x86/kvm/lapic.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","versions":[{"version":"01402cf81051f796dac7c60ca11d6147153ca46a","lessThan":"bf99ea52970caeb4583bdba1192c1f9b53b12c84","versionType":"git","status":"affected"},{"version":"01402cf81051f796dac7c60ca11d6147153ca46a","lessThan":"018685461a5b9a9a70e664ac77aef0d7415a3fd5","versionType":"git","status":"affected"},{"version":"01402cf81051f796dac7c60ca11d6147153ca46a","lessThan":"a2aff09807fbe4018c269d3773a629949058b210","versionType":"git","status":"affected"},{"version":"01402cf81051f796dac7c60ca11d6147153ca46a","lessThan":"218bf772bddd221489c38dde6ef8e917131161f6","versionType":"git","status":"affected"}]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","programFiles":["arch/x86/kvm/lapic.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","versions":[{"version":"5.3","status":"affected"},{"version":"0","lessThan":"5.3","versionType":"semver","status":"unaffected"},{"version":"5.4.128","lessThanOrEqual":"5.4.*","versionType":"semver","status":"unaffected"},{"version":"5.10.46","lessThanOrEqual":"5.10.*","versionType":"semver","status":"unaffected"},{"version":"5.12.13","lessThanOrEqual":"5.12.*","versionType":"semver","status":"unaffected"},{"version":"5.13","lessThanOrEqual":"*","versionType":"original_commit_for_fix","status":"unaffected"}]}]

Initial Analysis by NIST 4/30/2025 11:11:57 AM

Action	Type	New Value
Added	CVSS V3.1	AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H
Added	CWE	NVD-CWE-Other
Added	CPE Configuration	OR cpe:2.3:o:linux:linux_kernel:5.13:rc1::::::* cpe:2.3:o:linux:linux_kernel:5.13:rc2::::::* cpe:2.3:o:linux:linux_kernel:5.13:rc3::::::* cpe:2.3:o:linux:linux_kernel:5.13:rc4::::::* cpe:2.3:o:linux:linux_kernel:5.13:rc5::::::* cpe:2.3:o:linux:linux_kernel:5.13:rc6::::::* cpe:2.3:o:linux:linux_kernel::::::::* versions from (including) 5.3 up to (excluding) 5.4.128 cpe:2.3:o:linux:linux_kernel::::::::* versions from (including) 5.5 up to (excluding) 5.10.46 cpe:2.3:o:linux:linux_kernel::::::::* versions from (including) 5.11 up to (excluding) 5.12.13
Added	Reference Type	CVE: https://git.kernel.org/stable/c/018685461a5b9a9a70e664ac77aef0d7415a3fd5 Types: Patch
Added	Reference Type	CVE: https://git.kernel.org/stable/c/218bf772bddd221489c38dde6ef8e917131161f6 Types: Patch
Added	Reference Type	CVE: https://git.kernel.org/stable/c/a2aff09807fbe4018c269d3773a629949058b210 Types: Patch
Added	Reference Type	CVE: https://git.kernel.org/stable/c/bf99ea52970caeb4583bdba1192c1f9b53b12c84 Types: Patch
Added	Reference Type	kernel.org: https://git.kernel.org/stable/c/018685461a5b9a9a70e664ac77aef0d7415a3fd5 Types: Patch
Added	Reference Type	kernel.org: https://git.kernel.org/stable/c/218bf772bddd221489c38dde6ef8e917131161f6 Types: Patch
Added	Reference Type	kernel.org: https://git.kernel.org/stable/c/a2aff09807fbe4018c269d3773a629949058b210 Types: Patch
Added	Reference Type	kernel.org: https://git.kernel.org/stable/c/bf99ea52970caeb4583bdba1192c1f9b53b12c84 Types: Patch

CVE Modified by CVE 11/21/2024 1:35:44 AM

Action	Type	New Value
Added	Reference	https://git.kernel.org/stable/c/018685461a5b9a9a70e664ac77aef0d7415a3fd5
Added	Reference	https://git.kernel.org/stable/c/218bf772bddd221489c38dde6ef8e917131161f6
Added	Reference	https://git.kernel.org/stable/c/a2aff09807fbe4018c269d3773a629949058b210
Added	Reference	https://git.kernel.org/stable/c/bf99ea52970caeb4583bdba1192c1f9b53b12c84

New CVE Received from kernel.org 5/21/2024 11:15:14 AM

Action	Type	New Value
Added	Description	In the Linux kernel, the following vulnerability has been resolved: kvm: LAPIC: Restore guard to prevent illegal APIC register access Per the SDM, "any access that touches bytes 4 through 15 of an APIC register may cause undefined behavior and must not be executed." Worse, such an access in kvm_lapic_reg_read can result in a leak of kernel stack contents. Prior to commit 01402cf81051 ("kvm: LAPIC: write down valid APIC registers"), such an access was explicitly disallowed. Restore the guard that was removed in that commit.
Added	Reference	kernel.org https://git.kernel.org/stable/c/018685461a5b9a9a70e664ac77aef0d7415a3fd5 [No types assigned]
Added	Reference	kernel.org https://git.kernel.org/stable/c/218bf772bddd221489c38dde6ef8e917131161f6 [No types assigned]
Added	Reference	kernel.org https://git.kernel.org/stable/c/a2aff09807fbe4018c269d3773a629949058b210 [No types assigned]
Added	Reference	kernel.org https://git.kernel.org/stable/c/bf99ea52970caeb4583bdba1192c1f9b53b12c84 [No types assigned]

Quick Info

CVE Dictionary Entry:
CVE-2021-47255
NVD Published Date:
05/21/2024
NVD Last Modified:
06/17/2026
Source:
kernel.org

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Information Technology Laboratory

National Vulnerability Database

National Vulnerability Database

CVE-2021-47255 Detail

Description

Metrics

References to Advisories, Solutions, and Tools

Weakness Enumeration

Known Affected Software Configurations Switch to CPE 2.2

CPEs loading, please wait.

Change History

CVE Modified by CISA-ADP 6/17/2026 12:17:01 AM

CVE Modified by kernel.org 6/17/2026 12:17:01 AM

Initial Analysis by NIST 4/30/2025 11:11:57 AM

CVE Modified by CVE 11/21/2024 1:35:44 AM

CVE Modified by kernel.org 5/28/2024 4:15:51 PM

New CVE Received from kernel.org 5/21/2024 11:15:14 AM

Quick Info