Linux Kernel Vulnerability Affecting Memory Management by Vendor

CVE-2026-89758

What is CVE-2026-89758?

A vulnerability in the Linux kernel's memory management system was identified, specifically concerning how device-private PMD (Page Middle Directory) entries are handled during the migration of anonymous THP (Transparent Huge Pages) folios to device memory. This flaw can occur when an HMM-based GPU driver attempts to migrate THP folios, resulting in device-private PMDs that do not represent valid memory mappings. Consequently, calls to memory management functions like mbind(), migrate_pages(), or set_mempolicy() can lead to erroneous behavior, including VM_BUG_ON() errors and potential crashes due to invalid dereferences or isolation of unrelated folios from the LRU (Least Recently Used) cache. This vulnerability necessitates a careful review and adherence to updates that rectify PMD handling to protect system stability.

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