Error Handling Vulnerability in Linux Kernel's mshv Component

CVE-2026-43045

What is CVE-2026-43045?

The Linux kernel contains an error handling vulnerability within the mshv component, specifically in the pin_user_pages_fast function. This vulnerability arises from improper management of pinned pages, where a short pin count can be incorrectly treated as successful. This oversight can result in the usage of partially pinned memory regions, leading to memory corruption. Furthermore, if an error occurs during the pinning process, the control flow fails to adequately track already pinned pages, resulting in a page reference leak. Addressing these issues involves treating short pins as failures and ensuring accurate accounting of pinned pages during error conditions.

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