What is CVE-2021-47255?

CVE-2021-47255 is a High severity Linux kernel vulnerability with a CVSS score of 7.1 out of 10, affecting Linux kernel versions from 5.3 onward and patched in 5.4.128, 5.10.46, 5.12.13 and others. CVE-2021-47255 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.

What is the CVSS score for CVE-2021-47255?

CVE-2021-47255 has a CVSS score of 7.1 out of 10, rated High severity. The vector string is CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H.

Is there a patch available for CVE-2021-47255?

Yes, CVE-2021-47255 has been patched. Fixed versions include 5.4.128, 5.10.46, 5.12.13 and others. If you are running Linux kernel 5.3 or later up to the fix versions, apply the relevant patch for your kernel branch.

Is CVE-2021-47255 actively exploited?

CVE-2021-47255 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.

CVE-2021-47255

High

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.

Package Linux Kernel

Published 2024-05-21

Last modified 2025-04-30

CVSS version 3.1

Patch available

Yes

CVSS 3.1 score

7.1

out of 10

High

Attack Vector

Local

Attack Complexity

Low

Privileges Required

Low

User Interaction

None

Scope

Unchanged

Confidentiality

High

Integrity

None

Availability

High

Vector string

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

Affected versions

Linux kernel versions 5.3 and later are affected. Fixed in 5.4.128, 5.10.46, 5.12.13, 5.13 and their respective stable series.

Affected from

≥ 5.3

Fixed in

✓ 5.4.128 5.4.x ✓ 5.10.46 5.10.x ✓ 5.12.13 5.12.x ✓ 5.13

References

4 total

Kernel Git
https://git.kernel.org/stable/c/018685461a5b9a9a70e664ac77aef0d7415a3fd5

Patch
Kernel Git
https://git.kernel.org/stable/c/218bf772bddd221489c38dde6ef8e917131161f6

Patch
Kernel Git
https://git.kernel.org/stable/c/a2aff09807fbe4018c269d3773a629949058b210

Patch
Kernel Git
https://git.kernel.org/stable/c/bf99ea52970caeb4583bdba1192c1f9b53b12c84

Patch

Details

CVE ID CVE-2021-47255

Severity High

CVSS score 7.1 / 10

CVSS version 3.1

Published 2024-05-21

Modified 2025-04-30

KEV No

Patch

Yes

Package linux

Frequently asked questions

What is CVE-2021-47255?

CVE-2021-47255 is a High severity Linux kernel vulnerability with a CVSS score of 7.1 out of 10 . It affects Linux kernel versions from 5.3 onward and has been patched in 5.4.128, 5.10.46, 5.12.13 and others. CVE-2021-47255 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.
What is the CVSS score for CVE-2021-47255?

CVE-2021-47255 has a CVSS score of 7.1 out of 10, rated High severity (CVSS 3.1). The vector string is CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H.
Is there a patch available for CVE-2021-47255?

Yes. CVE-2021-47255 has been patched. Fixed versions include 5.4.128, 5.10.46, 5.12.13 and others. If you are running Linux kernel 5.3 or later up to the fix versions, apply the relevant patch for your kernel branch.
Is CVE-2021-47255 actively exploited?

No. CVE-2021-47255 has not been confirmed as actively exploited. It is not listed in the CISA Known Exploited Vulnerabilities (KEV) catalog.