Is CVE-2021-47255 in the CISA KEV catalog?

No. CVE-2021-47255 is not currently on the CISA Known Exploited Vulnerabilities list.

What is the CVSS severity of CVE-2021-47255?

CVE-2021-47255 has a CVSS v3 base score of 7.1 (HIGH).

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

CVE-2021-47255 has an EPSS score of 0.24% (15th percentile), estimating the probability of exploitation in the next 30 days.

How do I fix CVE-2021-47255?

Upgrade linux on debian 11 to 5.10.46-1 or later.

CVE & CISA-KEV Catalog

CVE-2021-47255

HIGH

7.1

CVSS v3

NVD

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.

How to fix

Remediation Available

linuxDebian

Fixed in:5.10.46-1CVE-2021-47255

Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.

CVSS v3 Vector

Exploitability

Attack VectorLocal

Attack ComplexityLow

Privileges RequiredLow

User InteractionNone

ScopeUnchanged

Impact

ConfidentialityHigh

IntegrityNone

AvailabilityHigh

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

Exploit Intelligence

0.24%probability of exploitation in 30 days

15thpercentile

Low risk: more likely to be exploited than 15% of all known CVEs.

References

Patch4

Embed a live status badge for CVE-2021-47255

Markdown

[![CVE-2021-47255](https://tridentstack.com/cve/badge/CVE-2021-47255.svg)](https://tridentstack.com/cve/CVE-2021-47255)

HTML

<a href="https://tridentstack.com/cve/CVE-2021-47255"><img src="https://tridentstack.com/cve/badge/CVE-2021-47255.svg" alt="CVE-2021-47255"></a>

Find and fix vulnerabilities across your fleet

TridentStack Control continuously scans your Windows, macOS, and Linux fleet for known vulnerabilities, prioritizes them by severity and active exploitation, and patches them automatically.

Start free

This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2025-04-30.