{"api_version":"1","generated_at":"2026-05-13T18:23:57+00:00","cve":"CVE-2026-43486","urls":{"html":"https://cve.report/CVE-2026-43486","api":"https://cve.report/api/cve/CVE-2026-43486.json","docs":"https://cve.report/api","cve_org":"https://www.cve.org/CVERecord?id=CVE-2026-43486","nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-43486"},"summary":{"title":"arm64: contpte: fix set_access_flags() no-op check for SMMU/ATS faults","description":"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.","state":"PUBLISHED","assigner":"Linux","published_at":"2026-05-13 16:16:51","updated_at":"2026-05-13 16:16:51"},"problem_types":[],"metrics":[],"references":[{"url":"https://git.kernel.org/stable/c/6f92a7a8b48a523f910ef25dd83808710724f59b","name":"https://git.kernel.org/stable/c/6f92a7a8b48a523f910ef25dd83808710724f59b","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/05d239f2c95e66e27e7fb4e99ee07eb56e3e34b0","name":"https://git.kernel.org/stable/c/05d239f2c95e66e27e7fb4e99ee07eb56e3e34b0","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/97c5550b763171dbef61e6239cab372b9f9cd4a2","name":"https://git.kernel.org/stable/c/97c5550b763171dbef61e6239cab372b9f9cd4a2","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/09d620555e59768776090073a2c59d2bc8506eb3","name":"https://git.kernel.org/stable/c/09d620555e59768776090073a2c59d2bc8506eb3","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-43486","name":"CVE Program record","refsource":"CVE.ORG","tags":["canonical"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-43486","name":"NVD vulnerability detail","refsource":"NVD","tags":["canonical","analysis"]}],"affected":[{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 4602e5757bcceb231c3a13c36c373ad4a750eddb 05d239f2c95e66e27e7fb4e99ee07eb56e3e34b0 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 4602e5757bcceb231c3a13c36c373ad4a750eddb 6f92a7a8b48a523f910ef25dd83808710724f59b git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 4602e5757bcceb231c3a13c36c373ad4a750eddb 09d620555e59768776090073a2c59d2bc8506eb3 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 4602e5757bcceb231c3a13c36c373ad4a750eddb 97c5550b763171dbef61e6239cab372b9f9cd4a2 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 6.9","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.9 semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.12.78 6.12.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.18.19 6.18.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.19.9 6.19.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.0 * original_commit_for_fix","platforms":[]}],"timeline":[],"solutions":[],"workarounds":[],"exploits":[],"credits":[],"nvd_cpes":[],"vendor_comments":[],"enrichments":{"kev":null,"epss":null,"legacy_qids":[]},"source_records":{"cve_program":{"containers":{"cna":{"affected":[{"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"}]}],"cpeApplicability":[{"nodes":[{"cpeMatch":[{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.12.78","versionStartIncluding":"6.9","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.18.19","versionStartIncluding":"6.9","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.19.9","versionStartIncluding":"6.9","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"7.0","versionStartIncluding":"6.9","vulnerable":true}],"negate":false,"operator":"OR"}]}],"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."}],"providerMetadata":{"dateUpdated":"2026-05-13T15:08:32.085Z","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux"},"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"}}},"cveMetadata":{"assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","assignerShortName":"Linux","cveId":"CVE-2026-43486","datePublished":"2026-05-13T15:08:32.085Z","dateReserved":"2026-05-01T14:12:56.012Z","dateUpdated":"2026-05-13T15:08:32.085Z","state":"PUBLISHED"},"dataType":"CVE_RECORD","dataVersion":"5.2"},"nvd":{"publishedDate":"2026-05-13 16:16:51","lastModifiedDate":"2026-05-13 16:16:51","problem_types":[],"metrics":[],"configurations":[]},"legacy_mitre":{"record":{"CveYear":"2026","CveId":"43486","Ordinal":"1","Title":"arm64: contpte: fix set_access_flags() no-op check for SMMU/ATS ","CVE":"CVE-2026-43486","Year":"2026"},"notes":[{"CveYear":"2026","CveId":"43486","Ordinal":"1","NoteData":"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.","Type":"Description","Title":"arm64: contpte: fix set_access_flags() no-op check for SMMU/ATS "}]}}}