Linux Kernel Vulnerability Affecting Page Table Synchronization

CVE-2025-39844

What is CVE-2025-39844?

A vulnerability exists in the Linux kernel that affects the synchronization of page tables during the initialization of vmemmap when using 4-level paging. This flaw can lead to intermittent boot failures and kernel panics due to unsynchronized page tables, where the new PGD entries may not be reflected across all tasks. This discrepancy may result in critical failures when the kernel accesses the vmemmap area before the corresponding top-level entries are synchronized. An improvement has been proposed to enhance the robustness of the synchronization process, thereby reducing the likelihood of future regressions and ensuring better stability in handling persistent memory.

References