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…
Does this matter?
High impact if exploited, but EPSS currently rates exploitation as unlikely (0.24%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.
Description
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 3.1
- 7.1 HIGHCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H
- EPSS
- 0.24% probability · 16th percentile
- CISA KEV
- Not listed
- Affected
- linux/linux kernel
- Source
- 416baaa9-dc9f-4396-8d5f-8c081fb06d67
References
- https://git.kernel.org/stable/c/018685461a5b9a9a70e664ac77aef0d7415a3fd5Patch
- https://git.kernel.org/stable/c/218bf772bddd221489c38dde6ef8e917131161f6Patch
- https://git.kernel.org/stable/c/a2aff09807fbe4018c269d3773a629949058b210Patch
- https://git.kernel.org/stable/c/bf99ea52970caeb4583bdba1192c1f9b53b12c84Patch
- https://git.kernel.org/stable/c/018685461a5b9a9a70e664ac77aef0d7415a3fd5Patch
- https://git.kernel.org/stable/c/218bf772bddd221489c38dde6ef8e917131161f6Patch
- https://git.kernel.org/stable/c/a2aff09807fbe4018c269d3773a629949058b210Patch
- https://git.kernel.org/stable/c/bf99ea52970caeb4583bdba1192c1f9b53b12c84Patch
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.