CVE-2021-43056: Medium severity linux kernel vulnerability

Published Oct 25, 2021
·
Updated

A denial of service problem was found in KVM specific to powerpc. In this flaw, a user with local access can confuse the host offline code, causing the guest to crash.

References:

https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=cdeb5d7d890e14f3b70e8087e745c4a6a7d9f337

Other sources

A denial of service problem was found in the Linux kernel's Kernel-based Virtual Machine (KVM) specific to PowerPC. In this flaw, a user with local access can confuse the host offline code, causing the guest to crash.

An issue was discovered in the Linux kernel for powerpc before 5.14.15. It allows a malicious KVM guest to crash the host, when the host is running on Power8, due to an arch/powerpc/kvm/book3shvrmhandlers.S implementation bug in the handling of the SRR1 register values.

Affected Software

7 affected componentsFixes available
redhat/kernel<0:4.18.0-372.9.1.el8
0:4.18.0-372.9.1.el8
redhat/kernel<5.15
5.15
Linux Linux kernel>=5.2<5.4.15
Fedoraproject Fedora=33
Fedoraproject Fedora=34
Fedoraproject Fedora=35
debian/linux
5.10.223-15.10.234-16.1.129-16.1.135-16.12.22-16.12.25-1

Remediation

Information

Mitigation for this issue is either not available or the currently available options don't meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base, or stability.

Event History

Oct 25, 2021
CVE Published
12:00 AM
Oct 28, 2021
CVE Published
via MITRE·03:13 AM
Data Sourced
via MITRE·03:13 AM
Description
Jan 12, 2024
Data Sourced
via Launchpad·12:01 AM
Description
Apr 28, 2025
Data Sourced
via Ubuntu·04:34 AM
RemedyDescriptionSeverityAffected Software

Parent advisories

This vulnerability appears in the following advisories.

Frequently Asked Questions

1

What is the severity of CVE-2021-43056?

CVE-2021-43056 has been classified as a denial of service vulnerability which may have a critical impact in certain environments.

2

How do I fix CVE-2021-43056?

To mitigate CVE-2021-43056, update to the recommended kernel versions provided by your Linux distribution.

3

Who is affected by CVE-2021-43056?

CVE-2021-43056 affects users of KVM on powerpc architecture, particularly those with local access.

4

What impact does CVE-2021-43056 have on systems?

CVE-2021-43056 can cause guest virtual machines to crash, impacting availability.

5

What versions of kernel are vulnerable to CVE-2021-43056?

Kernel versions prior to 0:4.18.0-372.9.1.el8 and various versions of Linux kernel up to 5.4.15 are vulnerable to CVE-2021-43056.

Contact

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