CVE-2025-39899

CVE-2025-39899 concerns the Linux kernel mm/userfaultfd path where, on 32-bit ARM with CONFIG_HIGHPTE, move_pages_pte() maps PTE pages using kmap_local_page() and must unmap them in LIFO order. The current code unmapped dst_pte then src_pte in the same sequence, violating LIFO and triggering a ku...