Vulnerability Details : CVE-2021-47255
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.
Products affected by CVE-2021-47255
- cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
- cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
- cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
- cpe:2.3:o:linux:linux_kernel:5.13:rc1:*:*:*:*:*:*
- cpe:2.3:o:linux:linux_kernel:5.13:rc2:*:*:*:*:*:*
- cpe:2.3:o:linux:linux_kernel:5.13:rc3:*:*:*:*:*:*
- cpe:2.3:o:linux:linux_kernel:5.13:rc4:*:*:*:*:*:*
- cpe:2.3:o:linux:linux_kernel:5.13:rc5:*:*:*:*:*:*
- cpe:2.3:o:linux:linux_kernel:5.13:rc6:*:*:*:*:*:*
Exploit prediction scoring system (EPSS) score for CVE-2021-47255
0.04%
Probability of exploitation activity in the next 30 days
EPSS Score History
~ 11 %
Percentile, the proportion of vulnerabilities that are scored at or less
CVSS scores for CVE-2021-47255
| Base Score | Base Severity | CVSS Vector | Exploitability Score | Impact Score | Score Source | First Seen |
|---|---|---|---|---|---|---|
|
7.1
|
HIGH | CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H |
1.8
|
5.2
|
NIST | 2025-04-30 |
References for CVE-2021-47255
-
https://git.kernel.org/stable/c/018685461a5b9a9a70e664ac77aef0d7415a3fd5
kvm: LAPIC: Restore guard to prevent illegal APIC register access - kernel/git/stable/linux.git - Linux kernel stable treePatch
-
https://git.kernel.org/stable/c/218bf772bddd221489c38dde6ef8e917131161f6
kvm: LAPIC: Restore guard to prevent illegal APIC register access - kernel/git/stable/linux.git - Linux kernel stable treePatch
-
https://git.kernel.org/stable/c/bf99ea52970caeb4583bdba1192c1f9b53b12c84
kvm: LAPIC: Restore guard to prevent illegal APIC register access - kernel/git/stable/linux.git - Linux kernel stable treePatch
-
https://git.kernel.org/stable/c/a2aff09807fbe4018c269d3773a629949058b210
kvm: LAPIC: Restore guard to prevent illegal APIC register access - kernel/git/stable/linux.git - Linux kernel stable treePatch
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