CVE-2026-43045 mshv: Fix error handling in mshv_region_pin
A flaw in the Linux kernel's mshv driver allows memory corruption due to improper error handling during page pinning, potentially enabling 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-2026-43045?
CVE-2026-43045 is a medium-severity memory corruption vulnerability in Linux kernel, published on 1 May 2026. 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:
mshv: Fix error handling in mshv_region_pin
The current error handling has two issues:
First, pin_user_pages_fast() can return a short pin count (less than requested but greater than zero) when it cannot pin all requested pages. This is treated as success, leading to partially pinned regions being used, which causes memory corruption.
Second, when an error occurs mid-loop, already pinned pages from the current batch are not properly accounted for before calling mshv_region_invalidate_pages(), causing a page reference leak.
Treat short pins as errors and fix partial batch accounting before cleanup.
Which versions are affected by CVE-2026-43045?
It affects 1 product.
Products include Linux kernel.
How do I fix CVE-2026-43045?
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-2026-43045 being exploited?
There is no known exploitation of CVE-2026-43045 in the wild and no public exploit code.
Other vulnerabilities in Linux kernel
Sources
Also known as BELL-CVE-2026-43045, DEBIAN-CVE-2026-43045, GHSA-v9h6-w2p5-9327, ROOT-OS-UBUNTU-2204-CVE-2026-43045, ROOT-OS-UBUNTU-2404-CVE-2026-43045, UBUNTU-CVE-2026-43045.