{"api_version":"1","generated_at":"2026-08-22T17:31:05+00:00","cve":"CVE-2026-72043","urls":{"html":"https://cve.report/CVE-2026-72043","api":"https://cve.report/api/cve/CVE-2026-72043.json","docs":"https://cve.report/api","cve_org":"https://www.cve.org/CVERecord?id=CVE-2026-72043","nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-72043"},"summary":{"title":"LoongArch: Fix missing dirty page tracking in {pte,pmd}_wrprotect()","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nLoongArch: Fix missing dirty page tracking in {pte,pmd}_wrprotect()\n\nWhen hardware page table walker (PTW) is enabled on LoongArch, the CPU\nmay set _PAGE_DIRTY directly in the page table entry during a write TLB\nmiss, without going through the software TLB store handler. The software\nTLB store handler (tlbex.S:254) sets both _PAGE_DIRTY and_PAGE_MODIFIED\ntogether:\n\n    ori t0, t0, (_PAGE_VALID | _PAGE_DIRTY | _PAGE_MODIFIED)\n\nSince hardware PTW only sets _PAGE_DIRTY, the software-only bit, i.e.\n_PAGE_MODIFIED is left unchanged. This creates a window where a PTE has\n_PAGE_DIRTY set (hardware knows the page is dirty) but _PAGE_MODIFIED\nclear (software is unaware).\n\nWhen fork()/clone() triggers copy-on-write, __copy_present_ptes() calls\npte_wrprotect(), which unconditionally clears both the _PAGE_WRITE and\n_PAGE_DIRTY bits:\n\n    pte_val(pte) &= ~(_PAGE_WRITE | _PAGE_DIRTY);\n\nSince _PAGE_MODIFIED was never set, the dirtiness information is lost\ncompletely. Subsequently, when memory pressure triggers page reclaim,\npage_mkclean() / try_to_unmap() sees the page as clean (i.e. pte_dirty()\nreturns false) and the page may be freed without writeback, causing data\ncorruption.\n\nFix this by propagating the _PAGE_DIRTY bit to the _PAGE_MODIFIED bit in\nboth pte_wrprotect() and pmd_wrprotect() before clearing writeable bits:\n\n    if (pte_val(pte) & _PAGE_DIRTY)\n        pte_val(pte) |= _PAGE_MODIFIED;\n\nThe pmd_wrprotect() fix handles the CONFIG_TRANSPARENT_HUGEPAGE case,\nwhere pmd entries need the same treatment.\n\nThis ensures the software dirty tracking bit (checked by pte_dirty() and\npmd_dirty(), which read both the _PAGE_DIRTY and _PAGE_MODIFIED bits) is\npreserved across fork COW write-protection.\n\nThe issue was found by the LTP madvise09 test case, which exercises page\nreclaim after \"madvise(MADV_FREE), write and fork\" operation sequence on\nprivate anonymous mappings.","state":"PUBLISHED","assigner":"Linux","published_at":"2026-08-15 06:21:13","updated_at":"2026-08-17 06:18:02"},"problem_types":[],"metrics":[{"version":"3.1","source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","type":"Secondary","score":"7.1","severity":"HIGH","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N","data":{"version":"3.1","vectorString":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N","baseScore":7.1,"baseSeverity":"HIGH","attackVector":"LOCAL","attackComplexity":"LOW","privilegesRequired":"LOW","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"HIGH","integrityImpact":"HIGH","availabilityImpact":"NONE"}},{"version":"3.1","source":"CNA","type":"DECLARED","score":"7.1","severity":"HIGH","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N","data":{"baseScore":7.1,"baseSeverity":"HIGH","vectorString":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N","version":"3.1"}}],"references":[{"url":"https://git.kernel.org/stable/c/e8a916579e427af32f2de8213dfa23c5df6e6664","name":"https://git.kernel.org/stable/c/e8a916579e427af32f2de8213dfa23c5df6e6664","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/e483da960892c41fa7f0cf0d2fc2410d65a483d6","name":"https://git.kernel.org/stable/c/e483da960892c41fa7f0cf0d2fc2410d65a483d6","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/018e9828eb523c638fa3d9bdf0fd4956b74555b2","name":"https://git.kernel.org/stable/c/018e9828eb523c638fa3d9bdf0fd4956b74555b2","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/a65f49b6f7ece756394f8f0e85570020e7fd0e35","name":"https://git.kernel.org/stable/c/a65f49b6f7ece756394f8f0e85570020e7fd0e35","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/76f88650763a35cbf1384c65d66d096fa31cc58d","name":"https://git.kernel.org/stable/c/76f88650763a35cbf1384c65d66d096fa31cc58d","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/39bb21a4bff0d70058bf752d7b5aa2e2ccc864a9","name":"https://git.kernel.org/stable/c/39bb21a4bff0d70058bf752d7b5aa2e2ccc864a9","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-72043","name":"CVE Program record","refsource":"CVE.ORG","tags":["canonical"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-72043","name":"NVD vulnerability detail","refsource":"NVD","tags":["canonical","analysis"]}],"affected":[{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 09cfefb7fa70c3af011b0db0a513fd80b2f18abc 76f88650763a35cbf1384c65d66d096fa31cc58d git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 09cfefb7fa70c3af011b0db0a513fd80b2f18abc e8a916579e427af32f2de8213dfa23c5df6e6664 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 09cfefb7fa70c3af011b0db0a513fd80b2f18abc 39bb21a4bff0d70058bf752d7b5aa2e2ccc864a9 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 09cfefb7fa70c3af011b0db0a513fd80b2f18abc a65f49b6f7ece756394f8f0e85570020e7fd0e35 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 09cfefb7fa70c3af011b0db0a513fd80b2f18abc e483da960892c41fa7f0cf0d2fc2410d65a483d6 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 09cfefb7fa70c3af011b0db0a513fd80b2f18abc 018e9828eb523c638fa3d9bdf0fd4956b74555b2 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 5.19","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 5.19 semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.1.178 6.1.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.6.145 6.6.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.12.97 6.12.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.18.40 6.18.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.1.5 7.1.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.2 * original_commit_for_fix","platforms":[]}],"timeline":[],"solutions":[],"workarounds":[],"exploits":[],"credits":[],"nvd_cpes":[],"vendor_comments":[],"enrichments":{"kev":null,"epss":{"cve_year":"2026","cve_id":"72043","cve":"CVE-2026-72043","epss":"0.001600000","percentile":"0.057380000","score_date":"2026-08-17","updated_at":"2026-08-18 00:11:47"},"legacy_qids":[]},"source_records":{"cve_program":{"containers":{"cna":{"affected":[{"defaultStatus":"unaffected","product":"Linux","programFiles":["arch/loongarch/include/asm/pgtable.h"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"lessThan":"76f88650763a35cbf1384c65d66d096fa31cc58d","status":"affected","version":"09cfefb7fa70c3af011b0db0a513fd80b2f18abc","versionType":"git"},{"lessThan":"e8a916579e427af32f2de8213dfa23c5df6e6664","status":"affected","version":"09cfefb7fa70c3af011b0db0a513fd80b2f18abc","versionType":"git"},{"lessThan":"39bb21a4bff0d70058bf752d7b5aa2e2ccc864a9","status":"affected","version":"09cfefb7fa70c3af011b0db0a513fd80b2f18abc","versionType":"git"},{"lessThan":"a65f49b6f7ece756394f8f0e85570020e7fd0e35","status":"affected","version":"09cfefb7fa70c3af011b0db0a513fd80b2f18abc","versionType":"git"},{"lessThan":"e483da960892c41fa7f0cf0d2fc2410d65a483d6","status":"affected","version":"09cfefb7fa70c3af011b0db0a513fd80b2f18abc","versionType":"git"},{"lessThan":"018e9828eb523c638fa3d9bdf0fd4956b74555b2","status":"affected","version":"09cfefb7fa70c3af011b0db0a513fd80b2f18abc","versionType":"git"}]},{"defaultStatus":"affected","product":"Linux","programFiles":["arch/loongarch/include/asm/pgtable.h"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"status":"affected","version":"5.19"},{"lessThan":"5.19","status":"unaffected","version":"0","versionType":"semver"},{"lessThanOrEqual":"6.1.*","status":"unaffected","version":"6.1.178","versionType":"semver"},{"lessThanOrEqual":"6.6.*","status":"unaffected","version":"6.6.145","versionType":"semver"},{"lessThanOrEqual":"6.12.*","status":"unaffected","version":"6.12.97","versionType":"semver"},{"lessThanOrEqual":"6.18.*","status":"unaffected","version":"6.18.40","versionType":"semver"},{"lessThanOrEqual":"7.1.*","status":"unaffected","version":"7.1.5","versionType":"semver"},{"lessThanOrEqual":"*","status":"unaffected","version":"7.2","versionType":"original_commit_for_fix"}]}],"cpeApplicability":[{"nodes":[{"cpeMatch":[{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.1.178","versionStartIncluding":"5.19","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.6.145","versionStartIncluding":"5.19","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.12.97","versionStartIncluding":"5.19","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.18.40","versionStartIncluding":"5.19","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"7.1.5","versionStartIncluding":"5.19","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"7.2","versionStartIncluding":"5.19","vulnerable":true}],"negate":false,"operator":"OR"}]}],"descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nLoongArch: Fix missing dirty page tracking in {pte,pmd}_wrprotect()\n\nWhen hardware page table walker (PTW) is enabled on LoongArch, the CPU\nmay set _PAGE_DIRTY directly in the page table entry during a write TLB\nmiss, without going through the software TLB store handler. The software\nTLB store handler (tlbex.S:254) sets both _PAGE_DIRTY and_PAGE_MODIFIED\ntogether:\n\n    ori t0, t0, (_PAGE_VALID | _PAGE_DIRTY | _PAGE_MODIFIED)\n\nSince hardware PTW only sets _PAGE_DIRTY, the software-only bit, i.e.\n_PAGE_MODIFIED is left unchanged. This creates a window where a PTE has\n_PAGE_DIRTY set (hardware knows the page is dirty) but _PAGE_MODIFIED\nclear (software is unaware).\n\nWhen fork()/clone() triggers copy-on-write, __copy_present_ptes() calls\npte_wrprotect(), which unconditionally clears both the _PAGE_WRITE and\n_PAGE_DIRTY bits:\n\n    pte_val(pte) &= ~(_PAGE_WRITE | _PAGE_DIRTY);\n\nSince _PAGE_MODIFIED was never set, the dirtiness information is lost\ncompletely. Subsequently, when memory pressure triggers page reclaim,\npage_mkclean() / try_to_unmap() sees the page as clean (i.e. pte_dirty()\nreturns false) and the page may be freed without writeback, causing data\ncorruption.\n\nFix this by propagating the _PAGE_DIRTY bit to the _PAGE_MODIFIED bit in\nboth pte_wrprotect() and pmd_wrprotect() before clearing writeable bits:\n\n    if (pte_val(pte) & _PAGE_DIRTY)\n        pte_val(pte) |= _PAGE_MODIFIED;\n\nThe pmd_wrprotect() fix handles the CONFIG_TRANSPARENT_HUGEPAGE case,\nwhere pmd entries need the same treatment.\n\nThis ensures the software dirty tracking bit (checked by pte_dirty() and\npmd_dirty(), which read both the _PAGE_DIRTY and _PAGE_MODIFIED bits) is\npreserved across fork COW write-protection.\n\nThe issue was found by the LTP madvise09 test case, which exercises page\nreclaim after \"madvise(MADV_FREE), write and fork\" operation sequence on\nprivate anonymous mappings."}],"metrics":[{"cvssV3_1":{"baseScore":7.1,"baseSeverity":"HIGH","vectorString":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N","version":"3.1"},"scenarios":[{"lang":"en","value":"AV:L - The bug is triggered via local syscalls (mmap/madvise/write/fork or clone) through dup_mmap()->copy_page_range()->pte_wrprotect() on LoongArch; it is not reachable from network-facing kernel services.\nAC:L - An unprivileged attacker can reliably reproduce the LTP madvise09 sequence (MADV_FREE, write, fork, then force reclaim) on LoongArch CPUs with hardware PTW; no races or victim-specific state beyond attacker-controlled memory pressure are required.\nPR:L - No special capabilities are needed; any local user can create private anonymous or file-backed COW mappings, write them, fork, and drive page reclaim using standard unprivileged syscalls.\nUI:N - Exploitation requires no action from another user; the attacker controls the full trigger sequence in their own process or in a service worker they operate.\nS:U - Impact is confined to kernel memory-management integrity on the host; it does not constitute a VM escape, sandbox escape, or IOMMU/DMA boundary bypass.\nC:H - Incorrectly treating hardware-dirty pages as clean during reclaim can free page frames without writeback or swap, leaving prior contents in the buddy allocator for reuse by other mappings and enabling cross-process information disclosure.\nI:H - Lost dirty tracking causes silent discard of modified pages during reclaim without writeback, corrupting private anonymous data and file-backed COW mappings when dirty pages are freed or swapped incorrectly.\nA:N - The defect causes silent data corruption rather than kernel oops, panic, or hang; the system remains operational even when pages are incorrectly reclaimed."}]}],"providerMetadata":{"dateUpdated":"2026-08-17T05:39:42.678Z","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux"},"references":[{"url":"https://git.kernel.org/stable/c/76f88650763a35cbf1384c65d66d096fa31cc58d"},{"url":"https://git.kernel.org/stable/c/e8a916579e427af32f2de8213dfa23c5df6e6664"},{"url":"https://git.kernel.org/stable/c/39bb21a4bff0d70058bf752d7b5aa2e2ccc864a9"},{"url":"https://git.kernel.org/stable/c/a65f49b6f7ece756394f8f0e85570020e7fd0e35"},{"url":"https://git.kernel.org/stable/c/e483da960892c41fa7f0cf0d2fc2410d65a483d6"},{"url":"https://git.kernel.org/stable/c/018e9828eb523c638fa3d9bdf0fd4956b74555b2"}],"title":"LoongArch: Fix missing dirty page tracking in {pte,pmd}_wrprotect()","x_generator":{"engine":"bippy-1.2.0"}}},"cveMetadata":{"assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","assignerShortName":"Linux","cveId":"CVE-2026-72043","datePublished":"2026-08-15T05:52:02.505Z","dateReserved":"2026-08-09T03:40:39.902Z","dateUpdated":"2026-08-17T05:39:42.678Z","state":"PUBLISHED"},"dataType":"CVE_RECORD","dataVersion":"5.2"},"nvd":{"publishedDate":"2026-08-15 06:21:13","lastModifiedDate":"2026-08-17 06:18:02","problem_types":[],"metrics":{"cvssMetricV31":[{"source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","type":"Secondary","cvssData":{"version":"3.1","vectorString":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N","baseScore":7.1,"baseSeverity":"HIGH","attackVector":"LOCAL","attackComplexity":"LOW","privilegesRequired":"LOW","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"HIGH","integrityImpact":"HIGH","availabilityImpact":"NONE"},"exploitabilityScore":1.8,"impactScore":5.2}]},"configurations":[]},"legacy_mitre":{"record":{"CveYear":"2026","CveId":"72043","Ordinal":"1","Title":"LoongArch: Fix missing dirty page tracking in {pte,pmd}_wrprotec","CVE":"CVE-2026-72043","Year":"2026"},"notes":[{"CveYear":"2026","CveId":"72043","Ordinal":"1","NoteData":"In the Linux kernel, the following vulnerability has been resolved:\n\nLoongArch: Fix missing dirty page tracking in {pte,pmd}_wrprotect()\n\nWhen hardware page table walker (PTW) is enabled on LoongArch, the CPU\nmay set _PAGE_DIRTY directly in the page table entry during a write TLB\nmiss, without going through the software TLB store handler. The software\nTLB store handler (tlbex.S:254) sets both _PAGE_DIRTY and_PAGE_MODIFIED\ntogether:\n\n    ori t0, t0, (_PAGE_VALID | _PAGE_DIRTY | _PAGE_MODIFIED)\n\nSince hardware PTW only sets _PAGE_DIRTY, the software-only bit, i.e.\n_PAGE_MODIFIED is left unchanged. This creates a window where a PTE has\n_PAGE_DIRTY set (hardware knows the page is dirty) but _PAGE_MODIFIED\nclear (software is unaware).\n\nWhen fork()/clone() triggers copy-on-write, __copy_present_ptes() calls\npte_wrprotect(), which unconditionally clears both the _PAGE_WRITE and\n_PAGE_DIRTY bits:\n\n    pte_val(pte) &= ~(_PAGE_WRITE | _PAGE_DIRTY);\n\nSince _PAGE_MODIFIED was never set, the dirtiness information is lost\ncompletely. Subsequently, when memory pressure triggers page reclaim,\npage_mkclean() / try_to_unmap() sees the page as clean (i.e. pte_dirty()\nreturns false) and the page may be freed without writeback, causing data\ncorruption.\n\nFix this by propagating the _PAGE_DIRTY bit to the _PAGE_MODIFIED bit in\nboth pte_wrprotect() and pmd_wrprotect() before clearing writeable bits:\n\n    if (pte_val(pte) & _PAGE_DIRTY)\n        pte_val(pte) |= _PAGE_MODIFIED;\n\nThe pmd_wrprotect() fix handles the CONFIG_TRANSPARENT_HUGEPAGE case,\nwhere pmd entries need the same treatment.\n\nThis ensures the software dirty tracking bit (checked by pte_dirty() and\npmd_dirty(), which read both the _PAGE_DIRTY and _PAGE_MODIFIED bits) is\npreserved across fork COW write-protection.\n\nThe issue was found by the LTP madvise09 test case, which exercises page\nreclaim after \"madvise(MADV_FREE), write and fork\" operation sequence on\nprivate anonymous mappings.","Type":"Description","Title":"LoongArch: Fix missing dirty page tracking in {pte,pmd}_wrprotec"}]}}}