CVE-2026-43486

{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-43486", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-05-01T14:12:56.012Z", "datePublished": "2026-05-13T15:08:32.085Z", "dateUpdated": "2026-05-13T15:08:32.085Z"}, "containers": {"cna": {"providerMetadata": {"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-05-13T15:08:32.085Z"}, "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\narm64: contpte: fix set_access_flags() no-op check for SMMU/ATS faults\n\ncontpte_ptep_set_access_flags() compared the gathered ptep_get() value\nagainst the requested entry to detect no-ops. ptep_get() ORs AF/dirty\nfrom all sub-PTEs in the CONT block, so a dirty sibling can make the\ntarget appear already-dirty. When the gathered value matches entry, the\nfunction returns 0 even though the target sub-PTE still has PTE_RDONLY\nset in hardware.\n\nFor a CPU with FEAT_HAFDBS this gathered view is fine, since hardware may\nset AF/dirty on any sub-PTE and CPU TLB behavior is effectively gathered\nacross the CONT range. But page-table walkers that evaluate each\ndescriptor individually (e.g. a CPU without DBM support, or an SMMU\nwithout HTTU, or with HA/HD disabled in CD.TCR) can keep faulting on the\nunchanged target sub-PTE, causing an infinite fault loop.\n\nGathering can therefore cause false no-ops when only a sibling has been\nupdated:\n - write faults: target still has PTE_RDONLY (needs PTE_RDONLY cleared)\n - read faults: target still lacks PTE_AF\n\nFix by checking each sub-PTE against the requested AF/dirty/write state\n(the same bits consumed by __ptep_set_access_flags()), using raw\nper-PTE values rather than the gathered ptep_get() view, before\nreturning no-op. Keep using the raw target PTE for the write-bit unfold\ndecision.\n\nPer Arm ARM (DDI 0487) D8.7.1 (\"The Contiguous bit\"), any sub-PTE in a CONT\nrange may become the effective cached translation and software must\nmaintain consistent attributes across the range."}], "affected": [{"product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": ["arch/arm64/mm/contpte.c"], "versions": [{"version": "4602e5757bcceb231c3a13c36c373ad4a750eddb", "lessThan": "05d239f2c95e66e27e7fb4e99ee07eb56e3e34b0", "status": "affected", "versionType": "git"}, {"version": "4602e5757bcceb231c3a13c36c373ad4a750eddb", "lessThan": "6f92a7a8b48a523f910ef25dd83808710724f59b", "status": "affected", "versionType": "git"}, {"version": "4602e5757bcceb231c3a13c36c373ad4a750eddb", "lessThan": "09d620555e59768776090073a2c59d2bc8506eb3", "status": "affected", "versionType": "git"}, {"version": "4602e5757bcceb231c3a13c36c373ad4a750eddb", "lessThan": "97c5550b763171dbef61e6239cab372b9f9cd4a2", "status": "affected", "versionType": "git"}]}, {"product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": ["arch/arm64/mm/contpte.c"], "versions": [{"version": "6.9", "status": "affected"}, {"version": "0", "lessThan": "6.9", "status": "unaffected", "versionType": "semver"}, {"version": "6.12.78", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.18.19", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.19.9", "lessThanOrEqual": "6.19.*", "status": "unaffected", "versionType": "semver"}, {"version": "7.0", "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": "6.9", "versionEndExcluding": "6.12.78"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.9", "versionEndExcluding": "6.18.19"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.9", "versionEndExcluding": "6.19.9"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.9", "versionEndExcluding": "7.0"}]}]}], "references": [{"url": "https://git.kernel.org/stable/c/05d239f2c95e66e27e7fb4e99ee07eb56e3e34b0"}, {"url": "https://git.kernel.org/stable/c/6f92a7a8b48a523f910ef25dd83808710724f59b"}, {"url": "https://git.kernel.org/stable/c/09d620555e59768776090073a2c59d2bc8506eb3"}, {"url": "https://git.kernel.org/stable/c/97c5550b763171dbef61e6239cab372b9f9cd4a2"}], "title": "arm64: contpte: fix set_access_flags() no-op check for SMMU/ATS faults", "x_generator": {"engine": "bippy-1.2.0"}}}}

{}

{"affected": [{"affectedData": [{"defaultStatus": "unaffected", "product": "Linux", "programFiles": ["arch/arm64/mm/contpte.c"], "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "versions": [{"lessThan": "05d239f2c95e66e27e7fb4e99ee07eb56e3e34b0", "status": "affected", "version": "4602e5757bcceb231c3a13c36c373ad4a750eddb", "versionType": "git"}, {"lessThan": "6f92a7a8b48a523f910ef25dd83808710724f59b", "status": "affected", "version": "4602e5757bcceb231c3a13c36c373ad4a750eddb", "versionType": "git"}, {"lessThan": "09d620555e59768776090073a2c59d2bc8506eb3", "status": "affected", "version": "4602e5757bcceb231c3a13c36c373ad4a750eddb", "versionType": "git"}, {"lessThan": "97c5550b763171dbef61e6239cab372b9f9cd4a2", "status": "affected", "version": "4602e5757bcceb231c3a13c36c373ad4a750eddb", "versionType": "git"}]}, {"defaultStatus": "affected", "product": "Linux", "programFiles": ["arch/arm64/mm/contpte.c"], "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "versions": [{"status": "affected", "version": "6.9"}, {"lessThan": "6.9", "status": "unaffected", "version": "0", "versionType": "semver"}, {"lessThanOrEqual": "6.12.*", "status": "unaffected", "version": "6.12.78", "versionType": "semver"}, {"lessThanOrEqual": "6.18.*", "status": "unaffected", "version": "6.18.19", "versionType": "semver"}, {"lessThanOrEqual": "6.19.*", "status": "unaffected", "version": "6.19.9", "versionType": "semver"}, {"lessThanOrEqual": "*", "status": "unaffected", "version": "7.0", "versionType": "original_commit_for_fix"}]}], "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}], "configurations": [{"nodes": [{"cpeMatch": [{"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "matchCriteriaId": "D1D90B78-24E3-418D-A238-3FE23C32239B", "versionEndExcluding": "6.12.78", "versionStartIncluding": "6.9", "vulnerable": true}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "matchCriteriaId": "D394AC60-6F28-435F-872A-CCDF384B8331", "versionEndExcluding": "6.18.19", "versionStartIncluding": "6.13", "vulnerable": true}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "matchCriteriaId": "E825E7C3-FEAC-4FD3-8A81-78D7387948C9", "versionEndExcluding": "6.19.9", "versionStartIncluding": "6.19", "vulnerable": true}, {"criteria": "cpe:2.3:o:linux:linux_kernel:7.0:rc1:*:*:*:*:*:*", "matchCriteriaId": "F253B622-8837-4245-BCE5-A7BF8FC76A16", "vulnerable": true}, {"criteria": "cpe:2.3:o:linux:linux_kernel:7.0:rc2:*:*:*:*:*:*", "matchCriteriaId": "4AE85AD8-4641-4E7C-A2F4-305E2CD9EE64", "vulnerable": true}], "negate": false, "operator": "OR"}]}], "cveTags": [], "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\narm64: contpte: fix set_access_flags() no-op check for SMMU/ATS faults\n\ncontpte_ptep_set_access_flags() compared the gathered ptep_get() value\nagainst the requested entry to detect no-ops. ptep_get() ORs AF/dirty\nfrom all sub-PTEs in the CONT block, so a dirty sibling can make the\ntarget appear already-dirty. When the gathered value matches entry, the\nfunction returns 0 even though the target sub-PTE still has PTE_RDONLY\nset in hardware.\n\nFor a CPU with FEAT_HAFDBS this gathered view is fine, since hardware may\nset AF/dirty on any sub-PTE and CPU TLB behavior is effectively gathered\nacross the CONT range. But page-table walkers that evaluate each\ndescriptor individually (e.g. a CPU without DBM support, or an SMMU\nwithout HTTU, or with HA/HD disabled in CD.TCR) can keep faulting on the\nunchanged target sub-PTE, causing an infinite fault loop.\n\nGathering can therefore cause false no-ops when only a sibling has been\nupdated:\n - write faults: target still has PTE_RDONLY (needs PTE_RDONLY cleared)\n - read faults: target still lacks PTE_AF\n\nFix by checking each sub-PTE against the requested AF/dirty/write state\n(the same bits consumed by __ptep_set_access_flags()), using raw\nper-PTE values rather than the gathered ptep_get() view, before\nreturning no-op. Keep using the raw target PTE for the write-bit unfold\ndecision.\n\nPer Arm ARM (DDI 0487) D8.7.1 (\"The Contiguous bit\"), any sub-PTE in a CONT\nrange may become the effective cached translation and software must\nmaintain consistent attributes across the range."}], "id": "CVE-2026-43486", "lastModified": "2026-06-26T19:23:45.627", "metrics": {"cvssMetricV31": [{"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": "2026-05-13T16:16:51.880", "references": [{"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"], "url": "https://git.kernel.org/stable/c/05d239f2c95e66e27e7fb4e99ee07eb56e3e34b0"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"], "url": "https://git.kernel.org/stable/c/09d620555e59768776090073a2c59d2bc8506eb3"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"], "url": "https://git.kernel.org/stable/c/6f92a7a8b48a523f910ef25dd83808710724f59b"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"], "url": "https://git.kernel.org/stable/c/97c5550b763171dbef61e6239cab372b9f9cd4a2"}], "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "vulnStatus": "Analyzed", "weaknesses": [{"description": [{"lang": "en", "value": "CWE-835"}], "source": "nvd@nist.gov", "type": "Primary"}]}

{"bugzilla": {"description": "kernel: arm64: contpte: fix set_access_flags() no-op check for SMMU/ATS faults", "id": "2477140", "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2477140"}, "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-835", "details": ["A flaw was found in the Linux kernel. The `contpte_ptep_set_access_flags()` function, responsible for managing contiguous page table entries (CONT PTEs) on ARM64 architectures, incorrectly determines when an access flag update is a no-op. This can occur when a sibling page table entry's dirty bit causes the target entry to appear already updated. Consequently, page-table walkers, such as those in a System Memory Management Unit (SMMU) or Address Translation Services (ATS), can enter an infinite fault loop, leading to a system crash and a Denial of Service (DoS)."], "name": "CVE-2026-43486", "package_state": [{"cpe": "cpe:/o:redhat:enterprise_linux:10", "fix_state": "Fix deferred", "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"}], "public_date": "2026-05-13T00:00:00Z", "references": ["https://www.cve.org/CVERecord?id=CVE-2026-43486\nhttps://nvd.nist.gov/vuln/detail/CVE-2026-43486\nhttps://lore.kernel.org/linux-cve-announce/2026051349-CVE-2026-43486-b3b9@gregkh/T"], "threat_severity": "Moderate"}

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