{"id":"CVE-2026-64302","summary":"x86/mm: Fix freeing of PMD-sized vmemmap pages","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nx86/mm: Fix freeing of PMD-sized vmemmap pages\n\nCommit bf9e4e30f353 (\"x86/mm: use pagetable_free()\"), switched from\nfreeing non-boot page tables through __free_pages() to\npagetable_free().\n\nHowever, the function is also called to free vmemmap pages.\n\nGiven that vmemmap pages are not page tables, already the page_ptdesc(page)\nis wrong. But worse, pagetable_free() calls:\n\n\t__free_pages(page, compound_order(page));\n\nSince vmemmap pages are not compound pages (see vmemmap_alloc_block())\n-- except for HVO, which doesn't apply here -- only first page of a\nPMD-sized vmemmap page is freed, leaking the other ones.\n\nFix it by properly decoupling pagetable and vmemmap freeing.\nfree_pagetable() no longer has to mess with SECTION_INFO, as only the\nvmemmap is marked like that in register_page_bootmem_memmap().\n\nThe indentation in remove_pmd_table() is messed up. Fix that while\ntouching it.\n\nBootmem info handling will soon be fixed up. For now, handle it\nsimilar to free_pagetable(), just avoiding the ifdef.\n\n[ dhansen: changelog munging. More imperative voice ]","modified":"2026-07-27T04:03:21.141991365Z","published":"2026-07-25T08:49:37.621Z","database_specific":{"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/64xxx/CVE-2026-64302.json","cna_assigner":"Linux"},"references":[{"type":"WEB","url":"https://git.kernel.org/stable/c/03f6ecbc446c33b38fd452cd3c494092a8116967"},{"type":"WEB","url":"https://git.kernel.org/stable/c/39406c05f8f150f1685839acd38ffdd69ff92031"},{"type":"WEB","url":"https://git.kernel.org/stable/c/add1e4112e00b619614784bf630aeebfdefa23e1"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/64xxx/CVE-2026-64302.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-64302"},{"type":"PACKAGE","url":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"a1593c90896babf33e947910c7aecb9f50bab993"},{"fixed":"add1e4112e00b619614784bf630aeebfdefa23e1"}]},{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"bf9e4e30f3538391745a99bc2268ec4f5e4a401e"},{"fixed":"03f6ecbc446c33b38fd452cd3c494092a8116967"},{"fixed":"39406c05f8f150f1685839acd38ffdd69ff92031"}]},{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"6.18.7"},{"fixed":"6.18.39"}]}],"versions":["v6.18.38","v6.18.37","v6.18.36","v6.18.35","v6.18.34","v6.18.33","v6.18.32","v6.18.31","v6.18.30","v6.18.29","v6.18.28","v6.18.27","v6.18.26","v6.18.25","v6.18.24","v6.18.23","v6.18.22","v6.18.21","v6.18.20","v6.18.19","v6.18.18","v6.18.17","v6.18.16","v6.18.15","v6.18.14","v6.18.13","v6.18.12","v6.18.11","v6.18.10","v6.18.9","v6.18.8","v6.18.7"],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-64302.json"}},{"package":{"name":"Kernel","ecosystem":"Linux"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"6.18.39"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.19.0"},{"fixed":"7.1.4"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-64302.json"}}],"schema_version":"1.7.5"}