{"id":"CVE-2024-35993","state":"PUBLISHED","title":"mm: turn folio_test_hugetlb into a PageType","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nmm: turn folio_test_hugetlb into a PageType\n\nThe current folio_test_hugetlb() can be fooled by a concurrent folio split\ninto returning true for a folio which has never belonged to hugetlbfs. \nThis can't happen if the caller holds a refcount on it, but we have a few\nplaces (memory-failure, compaction, procfs) which do not and should not\ntake a speculative reference.\n\nSince hugetlb pages do not use individual page mapcounts (they are always\nfully mapped and use the entire_mapcount field to record the number of\nmappings), the PageType field is available now that page_mapcount()\nignores the value in this field.\n\nIn compaction and with CONFIG_DEBUG_VM enabled, the current implementation\ncan result in an oops, as reported by Luis. This happens since 9c5ccf2db04b\n(\"mm: remove HUGETLB_PAGE_DTOR\") effectively added some VM_BUG_ON() checks\nin the PageHuge() testing path.\n\n[willy@infradead.org: update vmcoreinfo]","publishedAt":"2024-05-20T09:47:57.739Z","updatedAt":"2026-08-05T11:31:27.140Z","severity":{"score":7.8,"label":"High","version":"3.1","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","source":"Linux"},"assigner":"Linux","products":["Linux Linux"],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"9c5ccf2db04b8d7c3df363fdd4856c2b79ab2c6a","status":"affected","lessThan":"2431b5f2650dfc47ce782d1ca7b02d6b3916976f","versionType":"git"},{"version":"9c5ccf2db04b8d7c3df363fdd4856c2b79ab2c6a","status":"affected","lessThan":"9fdcc5b6359dfdaa52a55033bf50e2cedd66eb32","versionType":"git"},{"version":"9c5ccf2db04b8d7c3df363fdd4856c2b79ab2c6a","status":"affected","lessThan":"d99e3140a4d33e26066183ff727d8f02f56bec64","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["include/linux/page-flags.h","include/trace/events/mmflags.h","kernel/vmcore_info.c","mm/hugetlb.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"6.6","status":"affected"},{"version":"0","status":"unaffected","lessThan":"6.6","versionType":"semver"},{"version":"6.6.30","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.8.9","status":"unaffected","lessThanOrEqual":"6.8.*","versionType":"semver"},{"version":"6.9","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["include/linux/page-flags.h","include/trace/events/mmflags.h","kernel/vmcore_info.c","mm/hugetlb.c"]}],"references":["https://git.kernel.org/stable/c/2431b5f2650dfc47ce782d1ca7b02d6b3916976f","https://git.kernel.org/stable/c/9fdcc5b6359dfdaa52a55033bf50e2cedd66eb32","https://git.kernel.org/stable/c/d99e3140a4d33e26066183ff727d8f02f56bec64"],"weaknesses":[],"ingestedAt":"2026-10-29T20:07:30.303Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2024/35xxx/CVE-2024-35993.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2024-35993","state":"PUBLISHED","datePublished":"2024-05-20T09:47:57.739Z","dateUpdated":"2026-08-05T11:31:27.140Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2024-05-17T13:50:33.147Z"},"containers":{"cna":{"title":"mm: turn folio_test_hugetlb into a PageType","descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nmm: turn folio_test_hugetlb into a PageType\n\nThe current folio_test_hugetlb() can be fooled by a concurrent folio split\ninto returning true for a folio which has never belonged to hugetlbfs. \nThis can't happen if the caller holds a refcount on it, but we have a few\nplaces (memory-failure, compaction, procfs) which do not and should not\ntake a speculative reference.\n\nSince hugetlb pages do not use individual page mapcounts (they are always\nfully mapped and use the entire_mapcount field to record the number of\nmappings), the PageType field is available now that page_mapcount()\nignores the value in this field.\n\nIn compaction and with CONFIG_DEBUG_VM enabled, the current implementation\ncan result in an oops, as reported by Luis. This happens since 9c5ccf2db04b\n(\"mm: remove HUGETLB_PAGE_DTOR\") effectively added some VM_BUG_ON() checks\nin the PageHuge() testing path.\n\n[willy@infradead.org: update vmcoreinfo]"}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"9c5ccf2db04b8d7c3df363fdd4856c2b79ab2c6a","status":"affected","lessThan":"2431b5f2650dfc47ce782d1ca7b02d6b3916976f","versionType":"git"},{"version":"9c5ccf2db04b8d7c3df363fdd4856c2b79ab2c6a","status":"affected","lessThan":"9fdcc5b6359dfdaa52a55033bf50e2cedd66eb32","versionType":"git"},{"version":"9c5ccf2db04b8d7c3df363fdd4856c2b79ab2c6a","status":"affected","lessThan":"d99e3140a4d33e26066183ff727d8f02f56bec64","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["include/linux/page-flags.h","include/trace/events/mmflags.h","kernel/vmcore_info.c","mm/hugetlb.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"6.6","status":"affected"},{"version":"0","status":"unaffected","lessThan":"6.6","versionType":"semver"},{"version":"6.6.30","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.8.9","status":"unaffected","lessThanOrEqual":"6.8.*","versionType":"semver"},{"version":"6.9","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["include/linux/page-flags.h","include/trace/events/mmflags.h","kernel/vmcore_info.c","mm/hugetlb.c"]}],"references":[{"url":"https://git.kernel.org/stable/c/2431b5f2650dfc47ce782d1ca7b02d6b3916976f"},{"url":"https://git.kernel.org/stable/c/9fdcc5b6359dfdaa52a55033bf50e2cedd66eb32"},{"url":"https://git.kernel.org/stable/c/d99e3140a4d33e26066183ff727d8f02f56bec64"}],"metrics":[{"cvssV3_1":{"version":"3.1","vectorString":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","baseScore":7.8,"baseSeverity":"HIGH"},"scenarios":[{"lang":"en","value":"AV:L - The vulnerability is in core MM page-flag accessors reached via compaction, memory-failure and procfs; triggering it requires local execution to allocate/split THPs and drive compaction scans. There is no remote or adjacent-network path to this code.\nAC:L - This is a race the attacker creates on both sides — one set of threads forces THP splits via madvise(MADV_DONTNEED)/partial munmap while another drives compaction (memory pressure, THP faults, or CMA/dma-buf allocations), and compaction scans millions of PFNs per second, so the narrow window between the two loads is retried continuously at no cost.\nPR:L - Only an ordinary unprivileged local user is needed: THP allocation and splitting are unprivileged operations, and direct compaction plus alloc_contig_range (CMA/dma-buf heap, v4l2 videobuf2) are reachable from normal userspace on Android and embedded systems without any capability.\nUI:N - The attacker's own threads generate both the folio split and the compaction scan; no victim action or cooperation is required.\nS:U - The type confusion and resulting corruption stay within the kernel's own security authority; no VM, IOMMU or sandbox boundary is crossed.\nC:H - folio_test_hugetlb() misidentifies a THP as a hugetlb folio, causing the kernel to read and interpret THP tail-page fields (_flags_1/_flags_2, _hugetlb_subpool, _hugetlb_hwpoison) as hugetlb metadata; this type confusion and the resulting list/metadata corruption are leverageable for disclosure of kernel memory contents.\nI:H - Type confusion leads to hugetlb machinery mutating non-hugetlb state — isolate_hugetlb() performs list_move_tail() on a THP still on an LRU list and clears bits in folio->private, and folio_set_hugetlb_hwpoison() does llist_add() into fields overlapping a THP's _deferred_list, giving linked-list corruption and a write primitive.\nA:H - isolate_or_dissolve_huge_page() dereferences the NULL hstate returned by size_to_hstate() in hstate_is_gigantic() (h->order), producing a kernel oops, and with CONFIG_DEBUG_VM_PGFLAGS the VM_BUG_ON_PGFLAGS in folio_flags() panics the kernel — the originally reported symptom."}]}],"providerMetadata":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-08-05T11:31:27.140Z"},"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.6","versionEndExcluding":"6.6.30"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.6","versionEndExcluding":"6.8.9"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.6","versionEndExcluding":"6.9"}]}]}],"x_generator":{"engine":"bippy-1.2.0"}},"adp":[{"title":"CISA ADP Vulnrichment","metrics":[{"other":{"type":"ssvc","content":{"id":"CVE-2024-35993","role":"CISA Coordinator","options":[{"Exploitation":"none"},{"Automatable":"no"},{"Technical Impact":"partial"}],"version":"2.0.3","timestamp":"2024-05-20T14:06:03.625705Z"}}}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2024-06-04T17:33:44.623Z"}},{"title":"CVE Program Container","references":[{"url":"https://git.kernel.org/stable/c/2431b5f2650dfc47ce782d1ca7b02d6b3916976f","tags":["x_transferred"]},{"url":"https://git.kernel.org/stable/c/9fdcc5b6359dfdaa52a55033bf50e2cedd66eb32","tags":["x_transferred"]},{"url":"https://git.kernel.org/stable/c/d99e3140a4d33e26066183ff727d8f02f56bec64","tags":["x_transferred"]}],"providerMetadata":{"shortName":"CVE","orgId":"af854a3a-2127-422b-91ae-364da2661108","dateUpdated":"2024-08-02T03:30:12.237Z"}}]}}}