CVE-2021-47112 x86/kvm: Teardown PV features on boot CPU as well
A missing teardown of paravirtualization features on the boot CPU during hibernation restore allows a hypervisor to write to stale memory, potentially leading to code execution or privilege escalation.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2021-47112?
CVE-2021-47112 is a high-severity memory corruption vulnerability in Linux kernel, published on 15 Mar 2024. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
In the Linux kernel, the following vulnerability has been resolved:
x86/kvm: Teardown PV features on boot CPU as well
Various PV features (Async PF, PV EOI, steal time) work through memory shared with hypervisor and when we restore from hibernation we must properly teardown all these features to make sure hypervisor doesn't write to stale locations after we jump to the previously hibernated kernel (which can try to place anything there). For secondary CPUs the job is already done by kvm_cpu_down_prepare(), register syscore ops to do the same for boot CPU.
Which versions are affected by CVE-2021-47112?
It affects 1 product.
Products include Linux kernel.
How do I fix CVE-2021-47112?
Apply the vendor's patch.
Upgrade to the fixed version. Memory-safe languages, compiler hardening and fuzzing prevent most new cases. More about Memory corruption.
Is CVE-2021-47112 being exploited?
There is no known exploitation of CVE-2021-47112 in the wild and no public exploit code.
Other vulnerabilities in Linux kernel
Sources
Also known as DEBIAN-CVE-2021-47112, GHSA-fq4q-x842-fmrh, UBUNTU-CVE-2021-47112.