CVE-2024-50263

{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2024-50263", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2024-10-21T19:36:19.982Z", "datePublished": "2024-11-11T13:58:18.577Z", "dateUpdated": "2026-08-05T11:42:52.945Z"}, "containers": {"cna": {"providerMetadata": {"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-05T11:42:52.945Z"}, "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nfork: only invoke khugepaged, ksm hooks if no error\n\nThere is no reason to invoke these hooks early against an mm that is in an\nincomplete state.\n\nThe change in commit d24062914837 (\"fork: use __mt_dup() to duplicate\nmaple tree in dup_mmap()\") makes this more pertinent as we may be in a\nstate where entries in the maple tree are not yet consistent.\n\nTheir placement early in dup_mmap() only appears to have been meaningful\nfor early error checking, and since functionally it'd require a very small\nallocation to fail (in practice 'too small to fail') that'd only occur in\nthe most dire circumstances, meaning the fork would fail or be OOM'd in\nany case.\n\nSince both khugepaged and KSM tracking are there to provide optimisations\nto memory performance rather than critical functionality, it doesn't\nreally matter all that much if, under such dire memory pressure, we fail\nto register an mm with these.\n\nAs a result, we follow the example of commit d2081b2bf819 (\"mm:\nkhugepaged: make khugepaged_enter() void function\") and make ksm_fork() a\nvoid function also.\n\nWe only expose the mm to these functions once we are done with them and\nonly if no error occurred in the fork operation."}], "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 reached through ordinary local syscalls \u2014 `madvise(MADV_HUGEPAGE)`/`MADV_MERGEABLE` to register the mm with khugepaged/KSM, then `fork()`/`clone()` forced down an error path in `dup_mmap()`. No network or remote input is involved.\nAC:L - The attacker controls both sides of the race: they choose when the child mm is added to the khugepaged/KSM lists, they deterministically force the `dup_mmap()` error (e.g. SIGKILL landing in the VMA loop via `fatal_signal_pending(current)`, or ENOMEM under a self-imposed memcg limit), and KSM's blocking `mmap_read_lock(mm)` means ksmd is handed the lock the moment `dup_mmap()` unlocks. The attempt can be repeated indefinitely at no cost.\nPR:L - Only an unprivileged local user account is needed \u2014 `fork()`, `madvise()` and `prctl(PR_SET_MEMORY_MERGE)` require no capabilities, and no namespace tricks are necessary.\nUI:N - The attacker's own process performs the fork and the error injection; khugepaged/ksmd are always-running kernel threads. No victim action is required.\nS:U - The corruption is confined to kernel memory management structures within the same security authority; there is no VM, IOMMU or sandbox boundary crossed.\nC:H - khugepaged/KSM walk the child's maple tree containing the parent's VMAs and, once the parent unmaps them, freed `vm_area_struct`s \u2014 a use-after-free read of attacker-groomable heap memory, plus cross-address-space page/rmap confusion that can expose another address space's page contents.\nI:H - The scanners act on stale/foreign VMAs while installing PMDs and rewriting PTEs and rmap in the wrong mm (`collapse_file()`, `collapse_pte_mapped_thp()`, KSM's `try_to_merge_one_page()` with `vma->vm_mm != mm`), and dereference `vm_ops`/`anon_vma`/`vm_file` from freed objects \u2014 a UAF/type-confusion primitive usable for arbitrary write and control-flow hijack.\nA:H - At minimum the walkers dereference `XA_ZERO_ENTRY` (0x406) as a `struct vm_area_struct *`, producing a NULL-page kernel oops in khugepaged/ksmd; the use-after-free on parent VMAs likewise causes kernel crashes and, with `panic_on_oops`, a full panic."}]}], "affected": [{"product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": ["include/linux/ksm.h", "kernel/fork.c"], "versions": [{"version": "d2406291483775ecddaee929231a39c70c08fda2", "lessThan": "3b85aa0da8cd01173b9afd1f70080fbb9576c4b0", "status": "affected", "versionType": "git"}, {"version": "d2406291483775ecddaee929231a39c70c08fda2", "lessThan": "985da552a98e27096444508ce5d853244019111f", "status": "affected", "versionType": "git"}]}, {"product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": ["include/linux/ksm.h", "kernel/fork.c"], "versions": [{"version": "6.8", "status": "affected"}, {"version": "0", "lessThan": "6.8", "status": "unaffected", "versionType": "semver"}, {"version": "6.11.7", "lessThanOrEqual": "6.11.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.12", "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": "6.8", "versionEndExcluding": "6.11.7"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.8", "versionEndExcluding": "6.12"}]}]}], "references": [{"url": "https://git.kernel.org/stable/c/3b85aa0da8cd01173b9afd1f70080fbb9576c4b0"}, {"url": "https://git.kernel.org/stable/c/985da552a98e27096444508ce5d853244019111f"}, {"url": "https://project-zero.issues.chromium.org/issues/373391951"}], "title": "fork: only invoke khugepaged, ksm hooks if no error", "x_generator": {"engine": "bippy-1.2.0"}}}}

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{"affected": [{"affectedData": [{"defaultStatus": "unaffected", "product": "Linux", "programFiles": ["include/linux/ksm.h", "kernel/fork.c"], "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "versions": [{"lessThan": "3b85aa0da8cd01173b9afd1f70080fbb9576c4b0", "status": "affected", "version": "d2406291483775ecddaee929231a39c70c08fda2", "versionType": "git"}, {"lessThan": "985da552a98e27096444508ce5d853244019111f", "status": "affected", "version": "d2406291483775ecddaee929231a39c70c08fda2", "versionType": "git"}]}, {"defaultStatus": "affected", "product": "Linux", "programFiles": ["include/linux/ksm.h", "kernel/fork.c"], "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "versions": [{"status": "affected", "version": "6.8"}, {"lessThan": "6.8", "status": "unaffected", "version": "0", "versionType": "semver"}, {"lessThanOrEqual": "6.11.*", "status": "unaffected", "version": "6.11.7", "versionType": "semver"}, {"lessThanOrEqual": "*", "status": "unaffected", "version": "6.12", "versionType": "original_commit_for_fix"}]}], "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}], "configurations": [{"nodes": [{"cpeMatch": [{"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "matchCriteriaId": "40C0D9F3-9632-46FE-AA28-8CD73B52DEE7", "versionEndExcluding": "6.11.7", "versionStartIncluding": "6.8", "vulnerable": true}, {"criteria": "cpe:2.3:o:linux:linux_kernel:6.12:rc1:*:*:*:*:*:*", "matchCriteriaId": "7F361E1D-580F-4A2D-A509-7615F73167A1", "vulnerable": true}, {"criteria": "cpe:2.3:o:linux:linux_kernel:6.12:rc2:*:*:*:*:*:*", "matchCriteriaId": "925478D0-3E3D-4E6F-ACD5-09F28D5DF82C", "vulnerable": true}, {"criteria": "cpe:2.3:o:linux:linux_kernel:6.12:rc3:*:*:*:*:*:*", "matchCriteriaId": "3C95E234-D335-4B6C-96BF-E2CEBD8654ED", "vulnerable": true}, {"criteria": "cpe:2.3:o:linux:linux_kernel:6.12:rc4:*:*:*:*:*:*", "matchCriteriaId": "E0F717D8-3014-4F84-8086-0124B2111379", "vulnerable": true}, {"criteria": "cpe:2.3:o:linux:linux_kernel:6.12:rc5:*:*:*:*:*:*", "matchCriteriaId": "24DBE6C7-2AAE-4818-AED2-E131F153D2FA", "vulnerable": true}], "negate": false, "operator": "OR"}]}], "cveTags": [], "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nfork: only invoke khugepaged, ksm hooks if no error\n\nThere is no reason to invoke these hooks early against an mm that is in an\nincomplete state.\n\nThe change in commit d24062914837 (\"fork: use __mt_dup() to duplicate\nmaple tree in dup_mmap()\") makes this more pertinent as we may be in a\nstate where entries in the maple tree are not yet consistent.\n\nTheir placement early in dup_mmap() only appears to have been meaningful\nfor early error checking, and since functionally it'd require a very small\nallocation to fail (in practice 'too small to fail') that'd only occur in\nthe most dire circumstances, meaning the fork would fail or be OOM'd in\nany case.\n\nSince both khugepaged and KSM tracking are there to provide optimisations\nto memory performance rather than critical functionality, it doesn't\nreally matter all that much if, under such dire memory pressure, we fail\nto register an mm with these.\n\nAs a result, we follow the example of commit d2081b2bf819 (\"mm:\nkhugepaged: make khugepaged_enter() void function\") and make ksm_fork() a\nvoid function also.\n\nWe only expose the mm to these functions once we are done with them and\nonly if no error occurred in the fork operation."}, {"lang": "es", "value": "En el kernel de Linux, se ha resuelto la siguiente vulnerabilidad: fork: solo invocar ganchos khugepaged, ksm si no hay error No hay raz\u00f3n para invocar estos ganchos de manera temprana contra un mm que est\u00e1 en un estado incompleto. El cambio en el commit d24062914837 (\"fork: usar __mt_dup() para duplicar el \u00e1rbol de maple en dup_mmap()\") hace que esto sea m\u00e1s pertinente ya que podemos estar en un estado donde las entradas en el \u00e1rbol de maple a\u00fan no son consistentes. Su ubicaci\u00f3n temprana en dup_mmap() solo parece haber sido significativa para la comprobaci\u00f3n temprana de errores, y dado que funcionalmente requerir\u00eda una asignaci\u00f3n muy peque\u00f1a para fallar (en la pr\u00e1ctica 'demasiado peque\u00f1a para fallar') eso solo ocurrir\u00eda en las circunstancias m\u00e1s extremas, lo que significa que la bifurcaci\u00f3n fallar\u00eda o quedar\u00eda OOM en cualquier caso. Dado que tanto el seguimiento de khugepaged como el de KSM est\u00e1n ah\u00ed para proporcionar optimizaciones al rendimiento de la memoria en lugar de una funcionalidad cr\u00edtica, en realidad no importa tanto si, bajo una presi\u00f3n de memoria tan extrema, no logramos registrar un mm con estos. Como resultado, seguimos el ejemplo de el commit d2081b2bf819 (\"mm: khugepaged: make khugepaged_enter() void function\") y tambi\u00e9n hacemos que ksm_fork() sea una funci\u00f3n void. Solo exponemos el mm a estas funciones una vez que terminamos con ellas y solo si no ocurri\u00f3 ning\u00fan error en la operaci\u00f3n de bifurcaci\u00f3n."}], "id": "CVE-2024-50263", "lastModified": "2026-08-04T11:21:38.527", "metrics": {"cvssMetricV31": [{"cvssData": {"attackComplexity": "LOW", "attackVector": "LOCAL", "availabilityImpact": "HIGH", "baseScore": 7.8, "baseSeverity": "HIGH", "confidentialityImpact": "HIGH", "integrityImpact": "HIGH", "privilegesRequired": "LOW", "scope": "UNCHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H", "version": "3.1"}, "exploitabilityScore": 1.8, "impactScore": 5.9, "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "type": "Secondary"}, {"cvssData": {"attackComplexity": "LOW", "attackVector": "LOCAL", "availabilityImpact": "HIGH", "baseScore": 5.5, "baseSeverity": "MEDIUM", "confidentialityImpact": "NONE", "integrityImpact": "NONE", "privilegesRequired": "LOW", "scope": "UNCHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H", "version": "3.1"}, "exploitabilityScore": 1.8, "impactScore": 3.6, "source": "nvd@nist.gov", "type": "Primary"}]}, "published": "2024-11-11T14:15:15.473", "references": [{"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"], "url": "https://git.kernel.org/stable/c/3b85aa0da8cd01173b9afd1f70080fbb9576c4b0"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"], "url": "https://git.kernel.org/stable/c/985da552a98e27096444508ce5d853244019111f"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://project-zero.issues.chromium.org/issues/373391951"}], "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "vulnStatus": "Modified", "weaknesses": [{"description": [{"lang": "en", "value": "NVD-CWE-noinfo"}], "source": "nvd@nist.gov", "type": "Primary"}]}

{"bugzilla": {"description": "kernel: fork: only invoke khugepaged, ksm hooks if no error", "id": "2325208", "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2325208"}, "csaw": false, "cvss3": {"cvss3_base_score": "5.5", "cvss3_scoring_vector": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H", "status": "draft"}, "cwe": "CWE-99", "details": ["In the Linux kernel, the following vulnerability has been resolved:\nfork: only invoke khugepaged, ksm hooks if no error\nThere is no reason to invoke these hooks early against an mm that is in an\nincomplete state.\nThe change in commit d24062914837 (\"fork: use __mt_dup() to duplicate\nmaple tree in dup_mmap()\") makes this more pertinent as we may be in a\nstate where entries in the maple tree are not yet consistent.\nTheir placement early in dup_mmap() only appears to have been meaningful\nfor early error checking, and since functionally it'd require a very small\nallocation to fail (in practice 'too small to fail') that'd only occur in\nthe most dire circumstances, meaning the fork would fail or be OOM'd in\nany case.\nSince both khugepaged and KSM tracking are there to provide optimisations\nto memory performance rather than critical functionality, it doesn't\nreally matter all that much if, under such dire memory pressure, we fail\nto register an mm with these.\nAs a result, we follow the example of commit d2081b2bf819 (\"mm:\nkhugepaged: make khugepaged_enter() void function\") and make ksm_fork() a\nvoid function also.\nWe only expose the mm to these functions once we are done with them and\nonly if no error occurred in the fork operation."], "name": "CVE-2024-50263", "package_state": [{"cpe": "cpe:/o:redhat:enterprise_linux:6", "fix_state": "Out of support scope", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 6"}, {"cpe": "cpe:/o:redhat:enterprise_linux:7", "fix_state": "Out of support scope", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 7"}, {"cpe": "cpe:/o:redhat:enterprise_linux:7", "fix_state": "Out of support scope", "package_name": "kernel-rt", "product_name": "Red Hat Enterprise Linux 7"}, {"cpe": "cpe:/o:redhat:enterprise_linux:8", "fix_state": "Not affected", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 8"}, {"cpe": "cpe:/o:redhat:enterprise_linux:8", "fix_state": "Not affected", "package_name": "kernel-rt", "product_name": "Red Hat Enterprise Linux 8"}, {"cpe": "cpe:/o:redhat:enterprise_linux:9", "fix_state": "Not affected", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 9"}, {"cpe": "cpe:/o:redhat:enterprise_linux:9", "fix_state": "Not affected", "package_name": "kernel-rt", "product_name": "Red Hat Enterprise Linux 9"}], "public_date": "2024-11-11T00:00:00Z", "references": ["https://www.cve.org/CVERecord?id=CVE-2024-50263\nhttps://nvd.nist.gov/vuln/detail/CVE-2024-50263\nhttps://lore.kernel.org/linux-cve-announce/2024111122-CVE-2024-50263-5c65@gregkh/T"], "threat_severity": "Moderate"}

{}