CVE-2021-47255
highpriority · track · 28EPSS 0.002 · 16 %ileEURUUSEPSS · scored 2026-10-27
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.
cvss
Technical severity, 0–10. One row per scoring source.
base score 0–10 · higher = more severe · hover a vector to decode⚠ sources disagree · medium–high · 6.1–7.1
ssvc
A stakeholder decision — act, attend, or track — from exploitation and impact.
weaknesses
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affected products (18)
Products and version ranges known to be affected.
also known as (4)
Other names and identifiers for this entity.
sources
Which sources assert this record, and when.
references (13)
External citations — patches, advisories, analysis.
- https://cxsecurity.com/cveshow/CVE-2021-47255/cnnvd
- https://git.kernel.org/stable/c/018685461a5b9a9a70e664ac77aef0d7415a3fd5cnnvd
- https://git.kernel.org/stable/c/218bf772bddd221489c38dde6ef8e917131161f6cnnvd
- https://git.kernel.org/stable/c/a2aff09807fbe4018c269d3773a629949058b210cnnvd
- https://git.kernel.org/stable/c/bf99ea52970caeb4583bdba1192c1f9b53b12c84cnnvd
- https://git.kernel.org/stable/c/018685461a5b9a9a70e664ac77aef0d7415a3fd5enisa_euvd
- https://git.kernel.org/stable/c/218bf772bddd221489c38dde6ef8e917131161f6enisa_euvd
- https://git.kernel.org/stable/c/a2aff09807fbe4018c269d3773a629949058b210enisa_euvd
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