CVE-2021-47110
In the Linux kernel, the following vulnerability has been resolved: x86/kvm: Disable kvmclock on all CPUs on shutdown Currenly, we disable kvmclock from machine_shutdown() hook and this only happens for boot CPU.
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: x86/kvm: Disable kvmclock on all CPUs on shutdown Currenly, we disable kvmclock from machine_shutdown() hook and this only happens for boot CPU. We need to disable it for all CPUs to guard against memory corruption e.g. on restore from hibernate. Note, writing '0' to kvmclock MSR doesn't clear memory location, it just prevents hypervisor from updating the location so for the short while after write and while CPU is still alive, the clock remains usable and correct so we don't need to switch to some other clocksource.
- 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
- Weakness
- CWE-459
- Affected
- linux/linux kernel
- Source
- 416baaa9-dc9f-4396-8d5f-8c081fb06d67
References
- https://git.kernel.org/stable/c/1df2dc09926f61319116c80ee85701df33577d70Patch
- https://git.kernel.org/stable/c/3b0becf8b1ecf642a9edaf4c9628ffc641e490d6Patch
- https://git.kernel.org/stable/c/9084fe1b3572664ad276f427dce575f580c9799aPatch
- https://git.kernel.org/stable/c/c02027b5742b5aa804ef08a4a9db433295533046Patch
- https://git.kernel.org/stable/c/1df2dc09926f61319116c80ee85701df33577d70Patch
- https://git.kernel.org/stable/c/3b0becf8b1ecf642a9edaf4c9628ffc641e490d6Patch
- https://git.kernel.org/stable/c/9084fe1b3572664ad276f427dce575f580c9799aPatch
- https://git.kernel.org/stable/c/c02027b5742b5aa804ef08a4a9db433295533046Patch
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.