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CVE-2021-47228

6.2 · MEDIUM
Published May 21, 2024 linux EPSS 0.24% (15th pctl)

Overview

CVE-2021-47228 is a medium-severity vulnerability affecting linux linux_kernel. It was published on May 21, 2024 and has a CVSS 3.1 base score of 6.2 (MEDIUM).

This vulnerability has a CVSS 3.1 base score of 6.2, rated MEDIUM. It requires local or adjacent network access to exploit. No authentication or special privileges are required for exploitation.

Technical Description

In the Linux kernel, the following vulnerability has been resolved:

x86/ioremap: Map EFI-reserved memory as encrypted for SEV

Some drivers require memory that is marked as EFI boot services

data. In order for this memory to not be re-used by the kernel

after ExitBootServices(), efi_mem_reserve() is used to preserve it

by inserting a new EFI memory descriptor and marking it with the

EFI_MEMORY_RUNTIME attribute.

Under SEV, memory marked with the EFI_MEMORY_RUNTIME attribute needs to

be mapped encrypted by Linux, otherwise the kernel might crash at boot

like below:

EFI Variables Facility v0.08 2004-May-17

general protection fault, probably for non-canonical address 0x3597688770a868b2: 0000 [#1] SMP NOPTI

CPU: 13 PID: 1 Comm: swapper/0 Not tainted 5.12.4-2-default #1 openSUSE Tumbleweed

Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 0.0.0 02/06/2015

RIP: 0010:efi_mokvar_entry_next

[...]

Call Trace:

efi_mokvar_sysfs_init

? efi_mokvar_table_init

do_one_i

Remediation

Check the references section for vendor advisories and patches from linux. Update linux_kernel to the latest patched version. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

Affected Products

Vendor Product Versions Status
linux linux_kernel >= 5.10, < 5.10.46 Affected

Frequently Asked Questions

What is CVE-2021-47228?

CVE-2021-47228 is a medium-severity vulnerability affecting linux linux_kernel. It was published on May 21, 2024 and has a CVSS 3.1 base score of 6.2 (MEDIUM).

How severe is CVE-2021-47228?

This vulnerability has a CVSS 3.1 base score of 6.2, rated MEDIUM. It requires local or adjacent network access to exploit. No authentication or special privileges are required for exploitation.

How do I fix or remediate CVE-2021-47228?

Check the references section for vendor advisories and patches from linux. Update linux_kernel to the latest patched version. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

How can CyberStrike help with CVE-2021-47228?

CyberStrike's AI-powered security agents can automatically detect CVE-2021-47228 across your infrastructure using autonomous pentesting, DAST scanning, and HackBrowser. The platform continuously monitors for known vulnerabilities and provides actionable remediation guidance prioritized by real-world exploitability.