{"api_version":"1","generated_at":"2026-08-02T01:11:17+00:00","cve":"CVE-2026-64295","urls":{"html":"https://cve.report/CVE-2026-64295","api":"https://cve.report/api/cve/CVE-2026-64295.json","docs":"https://cve.report/api","cve_org":"https://www.cve.org/CVERecord?id=CVE-2026-64295","nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-64295"},"summary":{"title":"mm: page_ext: add count limit to page_ext_iter_next to prevent invalid PFN access","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nmm: page_ext: add count limit to page_ext_iter_next to prevent invalid PFN access\n\nThe page_ext iteration API does not validate if the PFN still belongs to a\nvalid section while advancing the iterator.  When dynamically adding\nmemory in the hotplug path, it can lead to a NULL pointer dereference\nduring page_ext_lookup at the boundary of the last valid section when\niterator count equals __pgcount.\n\nThe for_each_page_ext() macro calls page_ext_iter_next() as its loop\nincrement.  for_each_page_ext() does a \"__page_ext =\npage_ext_iter_next(&__iter)\" at the end.  This causes page_ext_iter_next()\nto increment iter->index past __pgcount and call page_ext_lookup(start_pfn\n+ __pgcount).  During memory hotplug (online), the PFN at start_pfn +\n__pgcount may belong to a section that has not yet been initialized,\ncausing page_ext_lookup() to trigger a NULL pointer dereference.\n\n[   14.555124][  T846] Call trace:\n[   14.555125][  T846]  lookup_page_ext+0x6c/0x108 (P)\n[   14.555127][  T846]  page_ext_lookup+0x30/0x3c\n[   14.555129][  T846]  __reset_page_owner+0x11c/0x260\n[   14.571201][  T846]  __free_pages_ok+0x5e8/0x8e0\n[   14.571204][  T846]  __free_pages_core+0x78/0xf0\n[   14.571206][  T846]  generic_online_page+0x14/0x24\n[   14.597782][  T846]  online_pages+0x178/0x30c\n[   14.597784][  T846]  memory_block_change_state+0x284/0x32c\n[   14.597787][  T846]  memory_subsys_online+0x4c/0x64\n[   14.597789][  T846]  device_online+0x88/0xb0\n[   14.597791][  T846]  online_memory_block+0x30/0x40\n[   14.597793][  T846]  walk_memory_blocks+0xac/0xe8\n[   14.597794][  T846]  add_memory_resource+0x280/0x298\n[   14.656161][  T846]  add_memory+0x60/0x98\n\nMove the iteration boundary enforcement inside the iterator functions, so\ncallers cannot inadvertently access beyond the requested range.","state":"PUBLISHED","assigner":"Linux","published_at":"2026-07-25 10:17:10","updated_at":"2026-07-30 15:00:27"},"problem_types":[],"metrics":[],"references":[{"url":"https://git.kernel.org/stable/c/8dcaa0f87a88d720d13106f3a306c6b61d189d86","name":"https://git.kernel.org/stable/c/8dcaa0f87a88d720d13106f3a306c6b61d189d86","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/ffd017237cfe99e6e5602ab14179b0e6878a0840","name":"https://git.kernel.org/stable/c/ffd017237cfe99e6e5602ab14179b0e6878a0840","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/377b1cd6bbcf327338cd951cc2fd74bc75540235","name":"https://git.kernel.org/stable/c/377b1cd6bbcf327338cd951cc2fd74bc75540235","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-64295","name":"CVE Program record","refsource":"CVE.ORG","tags":["canonical"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-64295","name":"NVD vulnerability detail","refsource":"NVD","tags":["canonical","analysis"]}],"affected":[{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 9039b9096ea27a20f0349d1537537663c935c8ed 8dcaa0f87a88d720d13106f3a306c6b61d189d86 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 9039b9096ea27a20f0349d1537537663c935c8ed 377b1cd6bbcf327338cd951cc2fd74bc75540235 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 9039b9096ea27a20f0349d1537537663c935c8ed ffd017237cfe99e6e5602ab14179b0e6878a0840 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 6.15","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.15 semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.18.39 6.18.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.1.4 7.1.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.2-rc3 * original_commit_for_fix","platforms":[]}],"timeline":[],"solutions":[],"workarounds":[],"exploits":[],"credits":[],"nvd_cpes":[],"vendor_comments":[],"enrichments":{"kev":null,"epss":{"cve_year":"2026","cve_id":"64295","cve":"CVE-2026-64295","epss":"0.002030000","percentile":"0.105080000","score_date":"2026-08-01","updated_at":"2026-08-02 00:11:13"},"legacy_qids":[]},"source_records":{"cve_program":{"containers":{"cna":{"affected":[{"defaultStatus":"unaffected","product":"Linux","programFiles":["include/linux/page_ext.h"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"lessThan":"8dcaa0f87a88d720d13106f3a306c6b61d189d86","status":"affected","version":"9039b9096ea27a20f0349d1537537663c935c8ed","versionType":"git"},{"lessThan":"377b1cd6bbcf327338cd951cc2fd74bc75540235","status":"affected","version":"9039b9096ea27a20f0349d1537537663c935c8ed","versionType":"git"},{"lessThan":"ffd017237cfe99e6e5602ab14179b0e6878a0840","status":"affected","version":"9039b9096ea27a20f0349d1537537663c935c8ed","versionType":"git"}]},{"defaultStatus":"affected","product":"Linux","programFiles":["include/linux/page_ext.h"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"status":"affected","version":"6.15"},{"lessThan":"6.15","status":"unaffected","version":"0","versionType":"semver"},{"lessThanOrEqual":"6.18.*","status":"unaffected","version":"6.18.39","versionType":"semver"},{"lessThanOrEqual":"7.1.*","status":"unaffected","version":"7.1.4","versionType":"semver"},{"lessThanOrEqual":"*","status":"unaffected","version":"7.2-rc3","versionType":"original_commit_for_fix"}]}],"cpeApplicability":[{"nodes":[{"cpeMatch":[{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.18.39","versionStartIncluding":"6.15","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"7.1.4","versionStartIncluding":"6.15","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"7.2-rc3","versionStartIncluding":"6.15","vulnerable":true}],"negate":false,"operator":"OR"}]}],"descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nmm: page_ext: add count limit to page_ext_iter_next to prevent invalid PFN access\n\nThe page_ext iteration API does not validate if the PFN still belongs to a\nvalid section while advancing the iterator.  When dynamically adding\nmemory in the hotplug path, it can lead to a NULL pointer dereference\nduring page_ext_lookup at the boundary of the last valid section when\niterator count equals __pgcount.\n\nThe for_each_page_ext() macro calls page_ext_iter_next() as its loop\nincrement.  for_each_page_ext() does a \"__page_ext =\npage_ext_iter_next(&__iter)\" at the end.  This causes page_ext_iter_next()\nto increment iter->index past __pgcount and call page_ext_lookup(start_pfn\n+ __pgcount).  During memory hotplug (online), the PFN at start_pfn +\n__pgcount may belong to a section that has not yet been initialized,\ncausing page_ext_lookup() to trigger a NULL pointer dereference.\n\n[   14.555124][  T846] Call trace:\n[   14.555125][  T846]  lookup_page_ext+0x6c/0x108 (P)\n[   14.555127][  T846]  page_ext_lookup+0x30/0x3c\n[   14.555129][  T846]  __reset_page_owner+0x11c/0x260\n[   14.571201][  T846]  __free_pages_ok+0x5e8/0x8e0\n[   14.571204][  T846]  __free_pages_core+0x78/0xf0\n[   14.571206][  T846]  generic_online_page+0x14/0x24\n[   14.597782][  T846]  online_pages+0x178/0x30c\n[   14.597784][  T846]  memory_block_change_state+0x284/0x32c\n[   14.597787][  T846]  memory_subsys_online+0x4c/0x64\n[   14.597789][  T846]  device_online+0x88/0xb0\n[   14.597791][  T846]  online_memory_block+0x30/0x40\n[   14.597793][  T846]  walk_memory_blocks+0xac/0xe8\n[   14.597794][  T846]  add_memory_resource+0x280/0x298\n[   14.656161][  T846]  add_memory+0x60/0x98\n\nMove the iteration boundary enforcement inside the iterator functions, so\ncallers cannot inadvertently access beyond the requested range."}],"providerMetadata":{"dateUpdated":"2026-07-25T08:49:33.194Z","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux"},"references":[{"url":"https://git.kernel.org/stable/c/8dcaa0f87a88d720d13106f3a306c6b61d189d86"},{"url":"https://git.kernel.org/stable/c/377b1cd6bbcf327338cd951cc2fd74bc75540235"},{"url":"https://git.kernel.org/stable/c/ffd017237cfe99e6e5602ab14179b0e6878a0840"}],"title":"mm: page_ext: add count limit to page_ext_iter_next to prevent invalid PFN access","x_generator":{"engine":"bippy-1.2.0"}}},"cveMetadata":{"assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","assignerShortName":"Linux","cveId":"CVE-2026-64295","datePublished":"2026-07-25T08:49:33.194Z","dateReserved":"2026-07-19T15:36:31.778Z","dateUpdated":"2026-07-25T08:49:33.194Z","state":"PUBLISHED"},"dataType":"CVE_RECORD","dataVersion":"5.2"},"nvd":{"publishedDate":"2026-07-25 10:17:10","lastModifiedDate":"2026-07-30 15:00:27","problem_types":[],"metrics":[],"configurations":[]},"legacy_mitre":{"record":{"CveYear":"2026","CveId":"64295","Ordinal":"1","Title":"mm: page_ext: add count limit to page_ext_iter_next to prevent i","CVE":"CVE-2026-64295","Year":"2026"},"notes":[{"CveYear":"2026","CveId":"64295","Ordinal":"1","NoteData":"In the Linux kernel, the following vulnerability has been resolved:\n\nmm: page_ext: add count limit to page_ext_iter_next to prevent invalid PFN access\n\nThe page_ext iteration API does not validate if the PFN still belongs to a\nvalid section while advancing the iterator.  When dynamically adding\nmemory in the hotplug path, it can lead to a NULL pointer dereference\nduring page_ext_lookup at the boundary of the last valid section when\niterator count equals __pgcount.\n\nThe for_each_page_ext() macro calls page_ext_iter_next() as its loop\nincrement.  for_each_page_ext() does a \"__page_ext =\npage_ext_iter_next(&__iter)\" at the end.  This causes page_ext_iter_next()\nto increment iter->index past __pgcount and call page_ext_lookup(start_pfn\n+ __pgcount).  During memory hotplug (online), the PFN at start_pfn +\n__pgcount may belong to a section that has not yet been initialized,\ncausing page_ext_lookup() to trigger a NULL pointer dereference.\n\n[   14.555124][  T846] Call trace:\n[   14.555125][  T846]  lookup_page_ext+0x6c/0x108 (P)\n[   14.555127][  T846]  page_ext_lookup+0x30/0x3c\n[   14.555129][  T846]  __reset_page_owner+0x11c/0x260\n[   14.571201][  T846]  __free_pages_ok+0x5e8/0x8e0\n[   14.571204][  T846]  __free_pages_core+0x78/0xf0\n[   14.571206][  T846]  generic_online_page+0x14/0x24\n[   14.597782][  T846]  online_pages+0x178/0x30c\n[   14.597784][  T846]  memory_block_change_state+0x284/0x32c\n[   14.597787][  T846]  memory_subsys_online+0x4c/0x64\n[   14.597789][  T846]  device_online+0x88/0xb0\n[   14.597791][  T846]  online_memory_block+0x30/0x40\n[   14.597793][  T846]  walk_memory_blocks+0xac/0xe8\n[   14.597794][  T846]  add_memory_resource+0x280/0x298\n[   14.656161][  T846]  add_memory+0x60/0x98\n\nMove the iteration boundary enforcement inside the iterator functions, so\ncallers cannot inadvertently access beyond the requested range.","Type":"Description","Title":"mm: page_ext: add count limit to page_ext_iter_next to prevent i"}]}}}