CVE-2022-49562 KVM: x86: Use __try_cmpxchg_user() to update guest PTE A/D bits
A flaw in Linux kernel KVM allows accessing random physical pages due to incorrect PTE handling, potentially leading to memory corruption and 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-2022-49562?
CVE-2022-49562 is a high-severity memory corruption vulnerability in Linux kernel, published on 26 Feb 2025. 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:
KVM: x86: Use __try_cmpxchg_user() to update guest PTE A/D bits
Use the recently introduced __try_cmpxchg_user() to update guest PTE A/D bits instead of mapping the PTE into kernel address space. The VM_PFNMAP path is broken as it assumes that vm_pgoff is the base pfn of the mapped VMA range, which is conceptually wrong as vm_pgoff is the offset relative to the file and has nothing to do with the pfn. The horrific hack worked for the original use case (backing guest memory with /dev/mem), but leads to accessing "random" pfns for pretty much any other VM_PFNMAP case.
Which versions are affected by CVE-2022-49562?
It affects 1 product.
Products include Linux kernel.
How do I fix CVE-2022-49562?
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-2022-49562 being exploited?
There is no known exploitation of CVE-2022-49562 in the wild and no public exploit code.
Other vulnerabilities in Linux kernel
Sources
Also known as AZL-68690, DEBIAN-CVE-2022-49562, GHSA-xpvw-h2w8-vrf9, ROOT-OS-DEBIAN-11-CVE-2022-49562, ROOT-OS-UBUNTU-2204-CVE-2022-49562, UBUNTU-CVE-2022-49562.