CVE-2026-68163

{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-68163", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-07-30T09:28:09.372Z", "datePublished": "2026-08-10T11:59:30.633Z", "dateUpdated": "2026-08-17T05:00:02.619Z"}, "containers": {"cna": {"providerMetadata": {"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-17T05:00:02.619Z"}, "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nmm/page_vma_mapped: fix device-private PMD handling\n\nCommit 65edfda6f3f2 (\"mm/rmap: extend rmap and migration support\ndevice-private entries\") introduced the concept of device-private PMD\nentries, but did not correctly update the rmap walk code to account for\nthem.\n\nAs a result, when page_vma_mapped_walk() encounters device-private PMD\nentries, it takes no action other than to acquire the PMD lock and exit.\n\nHowever this is highly problematic for two reasons - firstly, device\nprivate entries possess a PFN so check_pmd() needs to be called to ensure\nan overlapping PFN range.\n\nSecondly, and more importantly, if PVMW_MIGRATION is set the caller\nassumes the returned entry is a migration entry, resulting in memory\ncorruption when the caller tries to interpret the device private entry as\nsuch.\n\nIn addition, commit 146287290023 (\"mm/huge_memory: implement\ndevice-private THP splitting\") allowed device private PMDs to be split\nlike THP mappings, but again did not update this code path.\n\nAs a result, we might race a PMD split prior to acquiring the PMD lock.\n\nThis patch addresses all of these issues by invoking check_pmd(), ensuring\nPMVW_MIGRATION is not set and checks whether a split raced us we do for\nPMD THP and migration entries.\n\nInstead of checking for a subset of the cases after taking the pmd_lock(),\nput device-private along with pmd_trans_huge() and\npmd_is_migration_entry(). Also remove thp_migration_supported() as it is\nalready guarded by pmd_is_migration_entry().\n\n[akpm@linux-foundation.org: fix Raspberry Pi 1 build, per David]"}], "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 bug is in the MM rmap/page-table walk reached only from in-kernel memory-management paths (migrate_vma finalize, rmap unmap/migration) triggered by local syscalls and GPU driver ioctls (AMD KFD, nouveau, drm_pagemap), not from network packet handling.\nAC:L - An attacker with GPU/HMM access can reliably create device-private THP PMDs and drive migrate_vma/setup/finalize while racing PMD splits via concurrent threads; both sides of the race are attacker-controlled, not dependent on admin timing or uncontrollable layout.\nPR:L - Exploitation needs only an unprivileged local user who can use the GPU/HMM stack (typical render/video group access on ML/cloud GPU nodes) to allocate device-private THP and invoke migration; it does not require real root in the init namespace.\nUI:N - No victim interaction is required; memory migration and PMD splitting are driven entirely by the attacker's own process through normal GPU unified-memory/migration APIs and concurrent threads.\nS:U - Impact is kernel page-table corruption and local privilege escalation within the host kernel security domain; it is not a VM guest-to-host escape, IOMMU bypass, or cross-authority sandbox breakout per kernel CVSS scope guidance.\nC:H - Misinterpreting a device-private PMD as a migration entry corrupts page tables and rmap state; such MM corruption is readily weaponizable for arbitrary kernel memory reads, not merely a bounded leak.\nI:H - The faulty walk causes remove_migration_pmd() and related callers to install incorrect PMD/PTE contents from mis-typed entries, enabling arbitrary kernel memory writes and control-flow hijack via page-table manipulation.\nA:H - Incorrect PMD handling during migration or concurrent THP splitting can cause kernel oops/panic, use-after-free conditions, or hung migration paths, producing full system denial of service even before successful exploitation."}]}], "affected": [{"product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": ["mm/page_vma_mapped.c"], "versions": [{"version": "65edfda6f3f2e58f757485a056e4f1775a1404a8", "lessThan": "ab6209f4b48a98ef14d6766acdb62aa9bb32e670", "status": "affected", "versionType": "git"}, {"version": "65edfda6f3f2e58f757485a056e4f1775a1404a8", "lessThan": "f84ca9b1888d8fce7dfefe0e750fa971f8797486", "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/page_vma_mapped.c"], "versions": [{"version": "6.19", "status": "affected"}, {"version": "0", "lessThan": "6.19", "status": "unaffected", "versionType": "semver"}, {"version": "7.1.6", "lessThanOrEqual": "7.1.*", "status": "unaffected", "versionType": "semver"}, {"version": "7.2", "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": "6.19", "versionEndExcluding": "7.1.6"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.19", "versionEndExcluding": "7.2"}]}]}], "references": [{"url": "https://git.kernel.org/stable/c/ab6209f4b48a98ef14d6766acdb62aa9bb32e670"}, {"url": "https://git.kernel.org/stable/c/f84ca9b1888d8fce7dfefe0e750fa971f8797486"}], "title": "mm/page_vma_mapped: fix device-private PMD handling", "x_generator": {"engine": "bippy-1.2.0"}}}}

{}

{"affected": [{"affectedData": [{"defaultStatus": "unaffected", "product": "Linux", "programFiles": ["mm/page_vma_mapped.c"], "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "versions": [{"lessThan": "ab6209f4b48a98ef14d6766acdb62aa9bb32e670", "status": "affected", "version": "65edfda6f3f2e58f757485a056e4f1775a1404a8", "versionType": "git"}, {"lessThan": "f84ca9b1888d8fce7dfefe0e750fa971f8797486", "status": "affected", "version": "65edfda6f3f2e58f757485a056e4f1775a1404a8", "versionType": "git"}]}, {"defaultStatus": "affected", "product": "Linux", "programFiles": ["mm/page_vma_mapped.c"], "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "versions": [{"status": "affected", "version": "6.19"}, {"lessThan": "6.19", "status": "unaffected", "version": "0", "versionType": "semver"}, {"lessThanOrEqual": "7.1.*", "status": "unaffected", "version": "7.1.6", "versionType": "semver"}, {"lessThanOrEqual": "*", "status": "unaffected", "version": "7.2", "versionType": "original_commit_for_fix"}]}], "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}], "cveTags": [], "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nmm/page_vma_mapped: fix device-private PMD handling\n\nCommit 65edfda6f3f2 (\"mm/rmap: extend rmap and migration support\ndevice-private entries\") introduced the concept of device-private PMD\nentries, but did not correctly update the rmap walk code to account for\nthem.\n\nAs a result, when page_vma_mapped_walk() encounters device-private PMD\nentries, it takes no action other than to acquire the PMD lock and exit.\n\nHowever this is highly problematic for two reasons - firstly, device\nprivate entries possess a PFN so check_pmd() needs to be called to ensure\nan overlapping PFN range.\n\nSecondly, and more importantly, if PVMW_MIGRATION is set the caller\nassumes the returned entry is a migration entry, resulting in memory\ncorruption when the caller tries to interpret the device private entry as\nsuch.\n\nIn addition, commit 146287290023 (\"mm/huge_memory: implement\ndevice-private THP splitting\") allowed device private PMDs to be split\nlike THP mappings, but again did not update this code path.\n\nAs a result, we might race a PMD split prior to acquiring the PMD lock.\n\nThis patch addresses all of these issues by invoking check_pmd(), ensuring\nPMVW_MIGRATION is not set and checks whether a split raced us we do for\nPMD THP and migration entries.\n\nInstead of checking for a subset of the cases after taking the pmd_lock(),\nput device-private along with pmd_trans_huge() and\npmd_is_migration_entry(). Also remove thp_migration_supported() as it is\nalready guarded by pmd_is_migration_entry().\n\n[akpm@linux-foundation.org: fix Raspberry Pi 1 build, per David]"}], "id": "CVE-2026-68163", "lastModified": "2026-08-17T05:18:16.830", "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"}]}, "published": "2026-08-10T13:20:02.720", "references": [{"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/ab6209f4b48a98ef14d6766acdb62aa9bb32e670"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/f84ca9b1888d8fce7dfefe0e750fa971f8797486"}], "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "vulnStatus": "Received"}

{"bugzilla": {"description": "kernel: Linux kernel: Memory corruption due to incorrect device-private PMD handling", "id": "2513327", "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2513327"}, "csaw": false, "cvss3": {"cvss3_base_score": "5.2", "cvss3_scoring_vector": "CVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:U/C:L/I:L/A:H", "status": "draft"}, "cwe": "CWE-843", "details": ["In the Linux kernel, the following vulnerability has been resolved:\nmm/page_vma_mapped: fix device-private PMD handling\nCommit 65edfda6f3f2 (\"mm/rmap: extend rmap and migration support\ndevice-private entries\") introduced the concept of device-private PMD\nentries, but did not correctly update the rmap walk code to account for\nthem.\nAs a result, when page_vma_mapped_walk() encounters device-private PMD\nentries, it takes no action other than to acquire the PMD lock and exit.\nHowever this is highly problematic for two reasons - firstly, device\nprivate entries possess a PFN so check_pmd() needs to be called to ensure\nan overlapping PFN range.\nSecondly, and more importantly, if PVMW_MIGRATION is set the caller\nassumes the returned entry is a migration entry, resulting in memory\ncorruption when the caller tries to interpret the device private entry as\nsuch.\nIn addition, commit 146287290023 (\"mm/huge_memory: implement\ndevice-private THP splitting\") allowed device private PMDs to be split\nlike THP mappings, but again did not update this code path.\nAs a result, we might race a PMD split prior to acquiring the PMD lock.\nThis patch addresses all of these issues by invoking check_pmd(), ensuring\nPMVW_MIGRATION is not set and checks whether a split raced us we do for\nPMD THP and migration entries.\nInstead of checking for a subset of the cases after taking the pmd_lock(),\nput device-private along with pmd_trans_huge() and\npmd_is_migration_entry(). Also remove thp_migration_supported() as it is\nalready guarded by pmd_is_migration_entry().\n[akpm@linux-foundation.org: fix Raspberry Pi 1 build, per David]", "A flaw was found in the Linux kernel's memory management subsystem. Incorrect handling of device-private Page Middle Directory (PMD) entries can lead to memory corruption. Specifically, when `page_vma_mapped_walk()` encounters these entries, it can misinterpret them as migration entries, resulting in memory corruption. Additionally, a race condition can occur during PMD splitting, further contributing to memory integrity issues."], "name": "CVE-2026-68163", "package_state": [{"cpe": "cpe:/o:redhat:enterprise_linux:10", "fix_state": "Not affected", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 10"}, {"cpe": "cpe:/o:redhat:enterprise_linux:6", "fix_state": "Not affected", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 6"}, {"cpe": "cpe:/o:redhat:enterprise_linux:7", "fix_state": "Not affected", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 7"}, {"cpe": "cpe:/o:redhat:enterprise_linux:7", "fix_state": "Not affected", "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"}, {"cpe": "cpe:/a:redhat:enterprise_linux_nvidia:", "fix_state": "Not affected", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux for NVIDIA 26"}, {"cpe": "cpe:/a:redhat:openshift:4", "fix_state": "Not affected", "package_name": "rhcos", "product_name": "Red Hat OpenShift Container Platform 4"}], "public_date": "2026-08-10T11:59:30Z", "references": ["https://www.cve.org/CVERecord?id=CVE-2026-68163\nhttps://nvd.nist.gov/vuln/detail/CVE-2026-68163\nhttps://git.kernel.org/stable/c/ab6209f4b48a98ef14d6766acdb62aa9bb32e670\nhttps://git.kernel.org/stable/c/f84ca9b1888d8fce7dfefe0e750fa971f8797486"], "threat_severity": "Moderate"}

{"affected": [{"configurations": [{"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[65edfda6f3f2e58f757485a056e4f1775a1404a8,ab6209f4b48a98ef14d6766acdb62aa9bb32e670)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[65edfda6f3f2e58f757485a056e4f1775a1404a8,f84ca9b1888d8fce7dfefe0e750fa971f8797486)"}}], "enrichment": {"confidence": 99.0, "confidence_source": "inferred", "scores": [{"score": 99.0, "source": "inferred"}, {"score": 100.0, "source": "matching"}]}, "original": {"product": "Linux", "source": "cna", "vendor": "Linux"}, "product": "linux_kernel", "vendor": "linux"}, {"configurations": [{"platform": null, "status": "affected", "versions": {"scheme": "generic", "value": "6.19"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "generic", "value": "[0,6.19)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "generic", "value": "[0,7.2.0)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "generic", "value": "[7.2-rc5,*]"}}], "enrichment": {"confidence": 99.0, "confidence_source": "inferred", "scores": [{"score": 99.0, "source": "inferred"}, {"score": 100.0, "source": "matching"}]}, "original": {"product": "Linux", "source": "cna", "vendor": "Linux"}, "product": "linux_kernel", "vendor": "linux"}], "created": "2026-08-10T16:15:04.170175+00:00", "updated": "2026-08-14T00:00:04.143684+00:00", "vendors": ["linux", "linux$PRODUCT$linux_kernel"]}