{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2024-42234", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2024-07-30T07:40:12.252Z", "datePublished": "2024-08-07T15:14:24.467Z", "dateUpdated": "2026-08-05T11:35:59.332Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-05T11:35:59.332Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nmm: fix crashes from deferred split racing folio migration\n\nEven on 6.10-rc6, I've been seeing elusive \"Bad page state\"s (often on\nflags when freeing, yet the flags shown are not bad: PG_locked had been\nset and cleared??), and VM_BUG_ON_PAGE(page_ref_count(page) == 0)s from\ndeferred_split_scan()'s folio_put(), and a variety of other BUG and WARN\nsymptoms implying double free by deferred split and large folio migration.\n\n6.7 commit 9bcef5973e31 (\"mm: memcg: fix split queue list crash when large\nfolio migration\") was right to fix the memcg-dependent locking broken in\n85ce2c517ade (\"memcontrol: only transfer the memcg data for migration\"),\nbut missed a subtlety of deferred_split_scan(): it moves folios to its own\nlocal list to work on them without split_queue_lock, during which time\nfolio->_deferred_list is not empty, but even the \"right\" lock does nothing\nto secure the folio and the list it is on.\n\nFortunately, deferred_split_scan() is careful to use folio_try_get(): so\nfolio_migrate_mapping() can avoid the race by folio_undo_large_rmappable()\nwhile the old folio's reference count is temporarily frozen to 0 - adding\nsuch a freeze in the !mapping case too (originally, folio lock and\nunmapping and no swap cache left an anon folio unreachable, so no freezing\nwas needed there: but the deferred split queue offers a way to reach it)." } ], "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 (THP deferred split queue vs. folio migration) and is reached entirely through local syscalls — mmap/madvise(MADV_HUGEPAGE)/munmap to queue folios, memory pressure to invoke the shrinker, and move_pages/mbind or direct compaction to migrate them. No network or physical access is involved.\nAC:L - The attacker controls both sides of the race and can create it deliberately: one thread loops partial-unmapping large anon folios onto the deferred split queue while others generate reclaim pressure and issue move_pages()/fault THPs to drive migration of those same folios. Retrying is free and unlimited, and no attacker-independent condition is required — the race was hit even accidentally under ordinary load.\nPR:L - Only an ordinary unprivileged local user is needed; move_pages() on the caller's own process requires just ptrace_may_access() on self and MPOL_MF_MOVE, not CAP_SYS_NICE, and THP allocation, partial unmap, and memory pressure need no capabilities at all.\nUI:N - The attacking process performs all steps itself with no victim action required; the shrinker and compaction/migration paths run autonomously in kernel context.\nS:U - The corruption is of kernel page/folio state within the same security authority as the exploited kernel; no VM, IOMMU, or sandbox boundary is crossed.\nC:H - The double free / refcount underflow returns a page to the buddy allocator while it is still mapped into the attacker's address space, allowing that page to be reallocated as a kernel slab page, page table, or kernel stack and read directly from userspace, giving arbitrary kernel memory disclosure.\nI:H - The same cross-allocation aliasing gives an arbitrary kernel write primitive — the attacker retains a writable userspace mapping of a page the kernel has re-handed to internal structures — plus the list corruption itself writes attacker-influenced pointers into the global split queue, making control-flow hijack and privilege escalation feasible.\nA:H - The reported symptoms are outright kernel crashes — \"Bad page state\", VM_BUG_ON_PAGE(page_ref_count(page) == 0), list_del corruption BUGs and assorted WARNs from double free — any of which panics or destabilizes the system, and the condition can be triggered repeatedly." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "mm/memcontrol.c", "mm/migrate.c" ], "versions": [ { "version": "9bcef5973e31020e5aa8571eb994d67b77318356", "lessThan": "fc7facce686b64201dbf0b9614cc1d0bfad70010", "status": "affected", "versionType": "git" }, { "version": "9bcef5973e31020e5aa8571eb994d67b77318356", "lessThan": "be9581ea8c058d81154251cb0695987098996cad", "status": "affected", "versionType": "git" } ] }, { "product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "mm/memcontrol.c", "mm/migrate.c" ], "versions": [ { "version": "6.7", "status": "affected" }, { "version": "0", "lessThan": "6.7", "status": "unaffected", "versionType": "semver" }, { "version": "6.9.10", "lessThanOrEqual": "6.9.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.10", "lessThanOrEqual": "*", "status": "unaffected", "versionType": "original_commit_for_fix" } ] } ], "cpeApplicability": [ { "nodes": [ { "operator": "OR", "negate": false, "cpeMatch": [ { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.7", "versionEndExcluding": "6.9.10" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.7", "versionEndExcluding": "6.10" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/fc7facce686b64201dbf0b9614cc1d0bfad70010" }, { "url": "https://git.kernel.org/stable/c/be9581ea8c058d81154251cb0695987098996cad" } ], "title": "mm: fix crashes from deferred split racing folio migration", "x_generator": { "engine": "bippy-1.2.0" } }, "adp": [ { "metrics": [ { "other": { "type": "ssvc", "content": { "id": "CVE-2024-42234", "role": "CISA Coordinator", "options": [ { "Exploitation": "none" }, { "Automatable": "no" }, { "Technical Impact": "partial" } ], "version": "2.0.3", "timestamp": "2024-09-10T16:14:10.736603Z" } } } ], "title": "CISA ADP Vulnrichment", "providerMetadata": { "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "shortName": "CISA-ADP", "dateUpdated": "2024-09-11T17:34:32.409Z" } } ] } }