CVE-2021-43056
CVE-2021-43056 is a medium-severity vulnerability in Linux Linux Kernel with a CVSS 3.x base score of 5.5. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low.
Key facts
- Severity: Medium (CVSS 3.x base score 5.5)
- CVSS v2: 4.9
- EPSS exploit prediction: 0% (26th percentile)
- Actively exploited: Not listed in CISA KEV
- Affected product: Linux Linux Kernel
- Published:
- Last modified:
Description
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/book3s_hv_rmhandlers.S implementation bug in the handling of the SRR1 register values.
Frequently asked questions
- What is CVE-2021-43056?
- 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/book3s_hv_rmhandlers.S implementation bug in the handling of the SRR1 register values.
- How severe is CVE-2021-43056?
- CVE-2021-43056 has a CVSS 3.x base score of 5.5, rated medium severity. It is exploitable over local access with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.
- Is CVE-2021-43056 being actively exploited?
- It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (26th percentile), an estimate of the probability of exploitation in the next 30 days.
- What products are affected by CVE-2021-43056?
- CVE-2021-43056 primarily affects Linux Linux Kernel. In total, 4 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
- How do I fix CVE-2021-43056?
- Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
- When was CVE-2021-43056 published?
- CVE-2021-43056 was published on 2021-10-28 and last updated on 2026-06-17.
References
- http://www.openwall.com/lists/oss-security/2021/10/28/1
- https://cdn.kernel.org/pub/linux/kernel/v5.x/ChangeLog-5.14.15
- https://git.kernel.org/linus/cdeb5d7d890e14f3b70e8087e745c4a6a7d9f337
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/AA7EAPPKWG4LMTQQLNNSKATY6ST2KQFE/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/BBM4FP3IT3JZ2O7EBS7TEOG657N4ZGRE/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/RRAIS3PG4EV5WFLYESR6FXWM4BJJGWVA/
- https://lore.kernel.org/linuxppc-dev/87pmrtbbdt.fsf%40mpe.ellerman.id.au/T/#u
Affected products (4)
- cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
- cpe:2.3:o:fedoraproject:fedora:33:*:*:*:*:*:*:*
- cpe:2.3:o:fedoraproject:fedora:34:*:*:*:*:*:*:*
- cpe:2.3:o:fedoraproject:fedora:35:*:*:*:*:*:*:*
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