{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2021-47640", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2025-02-26T01:48:21.519Z", "datePublished": "2025-02-26T01:54:12.130Z", "dateUpdated": "2026-05-11T13:58:18.395Z"}, "containers": {"cna": {"providerMetadata": {"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-05-11T13:58:18.395Z"}, "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\npowerpc/kasan: Fix early region not updated correctly\n\nThe shadow's page table is not updated when PTE_RPN_SHIFT is 24\nand PAGE_SHIFT is 12. It not only causes false positives but\nalso false negative as shown the following text.\n\nFix it by bringing the logic of kasan_early_shadow_page_entry here.\n\n1. False Positive:\n==================================================================\nBUG: KASAN: vmalloc-out-of-bounds in pcpu_alloc+0x508/0xa50\nWrite of size 16 at addr f57f3be0 by task swapper/0/1\n\nCPU: 0 PID: 1 Comm: swapper/0 Not tainted 5.15.0-12267-gdebe436e77c7 #1\nCall Trace:\n[c80d1c20] [c07fe7b8] dump_stack_lvl+0x4c/0x6c (unreliable)\n[c80d1c40] [c02ff668] print_address_description.constprop.0+0x88/0x300\n[c80d1c70] [c02ff45c] kasan_report+0x1ec/0x200\n[c80d1cb0] [c0300b20] kasan_check_range+0x160/0x2f0\n[c80d1cc0] [c03018a4] memset+0x34/0x90\n[c80d1ce0] [c0280108] pcpu_alloc+0x508/0xa50\n[c80d1d40] [c02fd7bc] __kmem_cache_create+0xfc/0x570\n[c80d1d70] [c0283d64] kmem_cache_create_usercopy+0x274/0x3e0\n[c80d1db0] [c2036580] init_sd+0xc4/0x1d0\n[c80d1de0] [c00044a0] do_one_initcall+0xc0/0x33c\n[c80d1eb0] [c2001624] kernel_init_freeable+0x2c8/0x384\n[c80d1ef0] [c0004b14] kernel_init+0x24/0x170\n[c80d1f10] [c001b26c] ret_from_kernel_thread+0x5c/0x64\n\nMemory state around the buggy address:\n f57f3a80: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8\n f57f3b00: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8\n>f57f3b80: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8\n ^\n f57f3c00: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8\n f57f3c80: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8\n==================================================================\n\n2. False Negative (with KASAN tests):\n==================================================================\nBefore fix:\n ok 45 - kmalloc_double_kzfree\n # vmalloc_oob: EXPECTATION FAILED at lib/test_kasan.c:1039\n KASAN failure expected in \"((volatile char *)area)[3100]\", but none occurred\n not ok 46 - vmalloc_oob\n not ok 1 - kasan\n\n==================================================================\nAfter fix:\n ok 1 - kasan"}], "affected": [{"product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": ["arch/powerpc/mm/kasan/kasan_init_32.c"], "versions": [{"version": "cbd18991e24fea2c31da3bb117c83e4a3538cd11", "lessThan": "7f19245c3647afea8c7c41f795506ef70f64b9f2", "status": "affected", "versionType": "git"}, {"version": "cbd18991e24fea2c31da3bb117c83e4a3538cd11", "lessThan": "f39a3309393a4a484532f6ba745c6acbcfe06115", "status": "affected", "versionType": "git"}, {"version": "cbd18991e24fea2c31da3bb117c83e4a3538cd11", "lessThan": "5a3d8f3192a409893c57808cc935e16484df1068", "status": "affected", "versionType": "git"}, {"version": "cbd18991e24fea2c31da3bb117c83e4a3538cd11", "lessThan": "de56beace6648065d404cd9835aa7d30e3df519d", "status": "affected", "versionType": "git"}, {"version": "cbd18991e24fea2c31da3bb117c83e4a3538cd11", "lessThan": "e3d157a4b4f4e0268c98be5b7013bf4b31234bb6", "status": "affected", "versionType": "git"}, {"version": "cbd18991e24fea2c31da3bb117c83e4a3538cd11", "lessThan": "dd75080aa8409ce10d50fb58981c6b59bf8707d3", "status": "affected", "versionType": "git"}, {"version": "3822dd8c102d11ada9d9ed8e04cad0b347a04689", "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/powerpc/mm/kasan/kasan_init_32.c"], "versions": [{"version": "5.4", "status": "affected"}, {"version": "0", "lessThan": "5.4", "status": "unaffected", "versionType": "semver"}, {"version": "5.4.189", "lessThanOrEqual": "5.4.*", "status": "unaffected", "versionType": "semver"}, {"version": "5.10.110", "lessThanOrEqual": "5.10.*", "status": "unaffected", "versionType": "semver"}, {"version": "5.15.33", "lessThanOrEqual": "5.15.*", "status": "unaffected", "versionType": "semver"}, {"version": "5.16.19", "lessThanOrEqual": "5.16.*", "status": "unaffected", "versionType": "semver"}, {"version": "5.17.2", "lessThanOrEqual": "5.17.*", "status": "unaffected", "versionType": "semver"}, {"version": "5.18", "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": "5.4", "versionEndExcluding": "5.4.189"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.4", "versionEndExcluding": "5.10.110"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.4", "versionEndExcluding": "5.15.33"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.4", "versionEndExcluding": "5.16.19"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.4", "versionEndExcluding": "5.17.2"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.4", "versionEndExcluding": "5.18"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.3.6"}]}]}], "references": [{"url": "https://git.kernel.org/stable/c/7f19245c3647afea8c7c41f795506ef70f64b9f2"}, {"url": "https://git.kernel.org/stable/c/f39a3309393a4a484532f6ba745c6acbcfe06115"}, {"url": "https://git.kernel.org/stable/c/5a3d8f3192a409893c57808cc935e16484df1068"}, {"url": "https://git.kernel.org/stable/c/de56beace6648065d404cd9835aa7d30e3df519d"}, {"url": "https://git.kernel.org/stable/c/e3d157a4b4f4e0268c98be5b7013bf4b31234bb6"}, {"url": "https://git.kernel.org/stable/c/dd75080aa8409ce10d50fb58981c6b59bf8707d3"}], "title": "powerpc/kasan: Fix early region not updated correctly", "x_generator": {"engine": "bippy-1.2.0"}}, "adp": [{"metrics": [{"cvssV3_1": {"scope": "UNCHANGED", "version": "3.1", "baseScore": 7.8, "attackVector": "LOCAL", "baseSeverity": "HIGH", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H", "integrityImpact": "HIGH", "userInteraction": "NONE", "attackComplexity": "LOW", "availabilityImpact": "HIGH", "privilegesRequired": "LOW", "confidentialityImpact": "HIGH"}}, {"other": {"type": "ssvc", "content": {"id": "CVE-2021-47640", "role": "CISA Coordinator", "options": [{"Exploitation": "none"}, {"Automatable": "no"}, {"Technical Impact": "total"}], "version": "2.0.3", "timestamp": "2025-10-01T19:50:44.222623Z"}}}], "problemTypes": [{"descriptions": [{"lang": "en", "type": "CWE", "cweId": "CWE-787", "description": "CWE-787 Out-of-bounds Write"}]}], "title": "CISA ADP Vulnrichment", "providerMetadata": {"orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "shortName": "CISA-ADP", "dateUpdated": "2025-10-01T19:57:08.385Z"}}]}}

{"dataType": "CVE_RECORD", "containers": {"adp": [{"title": "CISA ADP Vulnrichment", "metrics": [{"cvssV3_1": {"scope": "UNCHANGED", "version": "3.1", "baseScore": 7.8, "attackVector": "LOCAL", "baseSeverity": "HIGH", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H", "integrityImpact": "HIGH", "userInteraction": "NONE", "attackComplexity": "LOW", "availabilityImpact": "HIGH", "privilegesRequired": "LOW", "confidentialityImpact": "HIGH"}}, {"other": {"type": "ssvc", "content": {"id": "CVE-2021-47640", "role": "CISA Coordinator", "options": [{"Exploitation": "none"}, {"Automatable": "no"}, {"Technical Impact": "total"}], "version": "2.0.3", "timestamp": "2025-10-01T19:50:44.222623Z"}}}], "problemTypes": [{"descriptions": [{"lang": "en", "type": "CWE", "cweId": "CWE-787", "description": "CWE-787 Out-of-bounds Write"}]}], "providerMetadata": {"orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "shortName": "CISA-ADP", "dateUpdated": "2025-10-01T16:01:44.600Z"}}], "cna": {"title": "powerpc/kasan: Fix early region not updated correctly", "affected": [{"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "product": "Linux", "versions": [{"status": "affected", "version": "cbd18991e24fea2c31da3bb117c83e4a3538cd11", "lessThan": "7f19245c3647afea8c7c41f795506ef70f64b9f2", "versionType": "git"}, {"status": "affected", "version": "cbd18991e24fea2c31da3bb117c83e4a3538cd11", "lessThan": "f39a3309393a4a484532f6ba745c6acbcfe06115", "versionType": "git"}, {"status": "affected", "version": "cbd18991e24fea2c31da3bb117c83e4a3538cd11", "lessThan": "5a3d8f3192a409893c57808cc935e16484df1068", "versionType": "git"}, {"status": "affected", "version": "cbd18991e24fea2c31da3bb117c83e4a3538cd11", "lessThan": "de56beace6648065d404cd9835aa7d30e3df519d", "versionType": "git"}, {"status": "affected", "version": "cbd18991e24fea2c31da3bb117c83e4a3538cd11", "lessThan": "e3d157a4b4f4e0268c98be5b7013bf4b31234bb6", "versionType": "git"}, {"status": "affected", "version": "cbd18991e24fea2c31da3bb117c83e4a3538cd11", "lessThan": "dd75080aa8409ce10d50fb58981c6b59bf8707d3", "versionType": "git"}, {"status": "affected", "version": "3822dd8c102d11ada9d9ed8e04cad0b347a04689", "versionType": "git"}], "programFiles": ["arch/powerpc/mm/kasan/kasan_init_32.c"], "defaultStatus": "unaffected"}, {"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "product": "Linux", "versions": [{"status": "affected", "version": "5.4"}, {"status": "unaffected", "version": "0", "lessThan": "5.4", "versionType": "semver"}, {"status": "unaffected", "version": "5.4.189", "versionType": "semver", "lessThanOrEqual": "5.4.*"}, {"status": "unaffected", "version": "5.10.110", "versionType": "semver", "lessThanOrEqual": "5.10.*"}, {"status": "unaffected", "version": "5.15.33", "versionType": "semver", "lessThanOrEqual": "5.15.*"}, {"status": "unaffected", "version": "5.16.19", "versionType": "semver", "lessThanOrEqual": "5.16.*"}, {"status": "unaffected", "version": "5.17.2", "versionType": "semver", "lessThanOrEqual": "5.17.*"}, {"status": "unaffected", "version": "5.18", "versionType": "original_commit_for_fix", "lessThanOrEqual": "*"}], "programFiles": ["arch/powerpc/mm/kasan/kasan_init_32.c"], "defaultStatus": "affected"}], "references": [{"url": "https://git.kernel.org/stable/c/7f19245c3647afea8c7c41f795506ef70f64b9f2"}, {"url": "https://git.kernel.org/stable/c/f39a3309393a4a484532f6ba745c6acbcfe06115"}, {"url": "https://git.kernel.org/stable/c/5a3d8f3192a409893c57808cc935e16484df1068"}, {"url": "https://git.kernel.org/stable/c/de56beace6648065d404cd9835aa7d30e3df519d"}, {"url": "https://git.kernel.org/stable/c/e3d157a4b4f4e0268c98be5b7013bf4b31234bb6"}, {"url": "https://git.kernel.org/stable/c/dd75080aa8409ce10d50fb58981c6b59bf8707d3"}], "x_generator": {"engine": "bippy-1.2.0"}, "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\npowerpc/kasan: Fix early region not updated correctly\n\nThe shadow's page table is not updated when PTE_RPN_SHIFT is 24\nand PAGE_SHIFT is 12. It not only causes false positives but\nalso false negative as shown the following text.\n\nFix it by bringing the logic of kasan_early_shadow_page_entry here.\n\n1. False Positive:\n==================================================================\nBUG: KASAN: vmalloc-out-of-bounds in pcpu_alloc+0x508/0xa50\nWrite of size 16 at addr f57f3be0 by task swapper/0/1\n\nCPU: 0 PID: 1 Comm: swapper/0 Not tainted 5.15.0-12267-gdebe436e77c7 #1\nCall Trace:\n[c80d1c20] [c07fe7b8] dump_stack_lvl+0x4c/0x6c (unreliable)\n[c80d1c40] [c02ff668] print_address_description.constprop.0+0x88/0x300\n[c80d1c70] [c02ff45c] kasan_report+0x1ec/0x200\n[c80d1cb0] [c0300b20] kasan_check_range+0x160/0x2f0\n[c80d1cc0] [c03018a4] memset+0x34/0x90\n[c80d1ce0] [c0280108] pcpu_alloc+0x508/0xa50\n[c80d1d40] [c02fd7bc] __kmem_cache_create+0xfc/0x570\n[c80d1d70] [c0283d64] kmem_cache_create_usercopy+0x274/0x3e0\n[c80d1db0] [c2036580] init_sd+0xc4/0x1d0\n[c80d1de0] [c00044a0] do_one_initcall+0xc0/0x33c\n[c80d1eb0] [c2001624] kernel_init_freeable+0x2c8/0x384\n[c80d1ef0] [c0004b14] kernel_init+0x24/0x170\n[c80d1f10] [c001b26c] ret_from_kernel_thread+0x5c/0x64\n\nMemory state around the buggy address:\n f57f3a80: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8\n f57f3b00: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8\n>f57f3b80: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8\n ^\n f57f3c00: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8\n f57f3c80: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8\n==================================================================\n\n2. False Negative (with KASAN tests):\n==================================================================\nBefore fix:\n ok 45 - kmalloc_double_kzfree\n # vmalloc_oob: EXPECTATION FAILED at lib/test_kasan.c:1039\n KASAN failure expected in \"((volatile char *)area)[3100]\", but none occurred\n not ok 46 - vmalloc_oob\n not ok 1 - kasan\n\n==================================================================\nAfter fix:\n ok 1 - kasan"}], "cpeApplicability": [{"nodes": [{"negate": false, "cpeMatch": [{"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "versionEndExcluding": "5.4.189", "versionStartIncluding": "5.4"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "versionEndExcluding": "5.10.110", "versionStartIncluding": "5.4"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "versionEndExcluding": "5.15.33", "versionStartIncluding": "5.4"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "versionEndExcluding": "5.16.19", "versionStartIncluding": "5.4"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "versionEndExcluding": "5.17.2", "versionStartIncluding": "5.4"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "versionEndExcluding": "5.18", "versionStartIncluding": "5.4"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "versionStartIncluding": "5.3.6"}], "operator": "OR"}]}], "providerMetadata": {"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-05-11T13:58:18.395Z"}}}, "cveMetadata": {"cveId": "CVE-2021-47640", "state": "PUBLISHED", "dateUpdated": "2026-05-11T13:58:18.395Z", "dateReserved": "2025-02-26T01:48:21.519Z", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "datePublished": "2025-02-26T01:54:12.130Z", "assignerShortName": "Linux"}, "dataVersion": "5.2"}

{"configurations": [{"nodes": [{"cpeMatch": [{"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "matchCriteriaId": "80DDFBB5-E7D8-4F00-9608-47CCB8D46CA4", "versionEndExcluding": "5.4.189", "versionStartIncluding": "5.4", "vulnerable": true}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "matchCriteriaId": "91D3BFD0-D3F3-4018-957C-96CCBF357D79", "versionEndExcluding": "5.10.110", "versionStartIncluding": "5.5", "vulnerable": true}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "matchCriteriaId": "27C42AE8-B387-43E2-938A-E1C8B40BE6D5", "versionEndExcluding": "5.15.33", "versionStartIncluding": "5.11", "vulnerable": true}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "matchCriteriaId": "20C43679-0439-405A-B97F-685BEE50613B", "versionEndExcluding": "5.16.19", "versionStartIncluding": "5.16", "vulnerable": true}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "matchCriteriaId": "210C679C-CF84-44A3-8939-E629C87E54BF", "versionEndExcluding": "5.17.2", "versionStartIncluding": "5.17", "vulnerable": true}], "negate": false, "operator": "OR"}]}], "cveTags": [], "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\npowerpc/kasan: Fix early region not updated correctly\n\nThe shadow's page table is not updated when PTE_RPN_SHIFT is 24\nand PAGE_SHIFT is 12. It not only causes false positives but\nalso false negative as shown the following text.\n\nFix it by bringing the logic of kasan_early_shadow_page_entry here.\n\n1. False Positive:\n==================================================================\nBUG: KASAN: vmalloc-out-of-bounds in pcpu_alloc+0x508/0xa50\nWrite of size 16 at addr f57f3be0 by task swapper/0/1\n\nCPU: 0 PID: 1 Comm: swapper/0 Not tainted 5.15.0-12267-gdebe436e77c7 #1\nCall Trace:\n[c80d1c20] [c07fe7b8] dump_stack_lvl+0x4c/0x6c (unreliable)\n[c80d1c40] [c02ff668] print_address_description.constprop.0+0x88/0x300\n[c80d1c70] [c02ff45c] kasan_report+0x1ec/0x200\n[c80d1cb0] [c0300b20] kasan_check_range+0x160/0x2f0\n[c80d1cc0] [c03018a4] memset+0x34/0x90\n[c80d1ce0] [c0280108] pcpu_alloc+0x508/0xa50\n[c80d1d40] [c02fd7bc] __kmem_cache_create+0xfc/0x570\n[c80d1d70] [c0283d64] kmem_cache_create_usercopy+0x274/0x3e0\n[c80d1db0] [c2036580] init_sd+0xc4/0x1d0\n[c80d1de0] [c00044a0] do_one_initcall+0xc0/0x33c\n[c80d1eb0] [c2001624] kernel_init_freeable+0x2c8/0x384\n[c80d1ef0] [c0004b14] kernel_init+0x24/0x170\n[c80d1f10] [c001b26c] ret_from_kernel_thread+0x5c/0x64\n\nMemory state around the buggy address:\n f57f3a80: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8\n f57f3b00: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8\n>f57f3b80: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8\n ^\n f57f3c00: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8\n f57f3c80: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8\n==================================================================\n\n2. False Negative (with KASAN tests):\n==================================================================\nBefore fix:\n ok 45 - kmalloc_double_kzfree\n # vmalloc_oob: EXPECTATION FAILED at lib/test_kasan.c:1039\n KASAN failure expected in \"((volatile char *)area)[3100]\", but none occurred\n not ok 46 - vmalloc_oob\n not ok 1 - kasan\n\n==================================================================\nAfter fix:\n ok 1 - kasan"}, {"lang": "es", "value": "En el kernel de Linux, se ha resuelto la siguiente vulnerabilidad: powerpc/kasan: Se solucion\u00f3 que la regi\u00f3n temprana no se actualizara correctamente La tabla de p\u00e1ginas de shadow no se actualiza cuando PTE_RPN_SHIFT es 24 y PAGE_SHIFT es 12. No solo causa falsos positivos sino tambi\u00e9n falsos negativos como se muestra en el siguiente texto. Arr\u00e9glelo trayendo la l\u00f3gica de kasan_early_shadow_page_entry aqu\u00ed. 1. Falso positivo: ==================================================================== ERROR: KASAN: vmalloc fuera de los l\u00edmites en pcpu_alloc+0x508/0xa50 Escritura de tama\u00f1o 16 en la direcci\u00f3n f57f3be0 por la tarea swapper/0/1 CPU: 0 PID: 1 Comm: swapper/0 No contaminado 5.15.0-12267-gdebe436e77c7 #1 Seguimiento de llamadas: [c80d1c20] [c07fe7b8] dump_stack_lvl+0x4c/0x6c (no confiable) [c80d1c40] [c02ff668] print_address_description.constprop.0+0x88/0x300 [c80d1c70] [c02ff45c] kasan_report+0x1ec/0x200 [c80d1cb0] [c0300b20] kasan_check_range+0x160/0x2f0 [c80d1cc0] [c03018a4] memset+0x34/0x90 [c80d1ce0] [c0280108] pcpu_alloc+0x508/0xa50 [c80d1d40] [c02fd7bc] __kmem_cache_create+0xfc/0x570 [c80d1d70] [c0283d64] kmem_cache_create_usercopy+0x274/0x3e0 [c80d1db0] [c2036580] init_sd+0xc4/0x1d0 [c80d1de0] [c00044a0] do_one_initcall+0xc0/0x33c [c80d1eb0] [c2001624] kernel_init_freeable+0x2c8/0x384 [c80d1ef0] [c0004b14] kernel_init+0x24/0x170 [c80d1f10] [c001b26c] ret_from_kernel_thread+0x5c/0x64 Estado de la memoria alrededor de la direcci\u00f3n con errores: f57f3a80: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f57f3b00: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 >f57f3b80: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 ^ f57f3c80: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 ===================================================================== 2. Falso negativo (con pruebas KASAN): ==================================================================== Antes de la correcci\u00f3n: ok 45 - kmalloc_double_kzfree # vmalloc_oob: EXPECTATIVA FALL\u00d3 en lib/test_kasan.c:1039 Se esperaba una falla de KASAN en \"((volatile char *)area)[3100]\", pero no ocurri\u00f3 ninguna no ok 46 - vmalloc_oob no ok 1 - kasan ======================================================================== Despu\u00e9s de la correcci\u00f3n: ok 1 - kasan"}], "id": "CVE-2021-47640", "lastModified": "2025-10-01T20:15:41.060", "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": "nvd@nist.gov", "type": "Primary"}, {"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": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "type": "Secondary"}]}, "published": "2025-02-26T06:37:05.780", "references": [{"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"], "url": "https://git.kernel.org/stable/c/5a3d8f3192a409893c57808cc935e16484df1068"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"], "url": "https://git.kernel.org/stable/c/7f19245c3647afea8c7c41f795506ef70f64b9f2"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"], "url": "https://git.kernel.org/stable/c/dd75080aa8409ce10d50fb58981c6b59bf8707d3"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"], "url": "https://git.kernel.org/stable/c/de56beace6648065d404cd9835aa7d30e3df519d"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"], "url": "https://git.kernel.org/stable/c/e3d157a4b4f4e0268c98be5b7013bf4b31234bb6"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"], "url": "https://git.kernel.org/stable/c/f39a3309393a4a484532f6ba745c6acbcfe06115"}], "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "vulnStatus": "Modified", "weaknesses": [{"description": [{"lang": "en", "value": "CWE-787"}], "source": "nvd@nist.gov", "type": "Primary"}, {"description": [{"lang": "en", "value": "CWE-787"}], "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "type": "Secondary"}]}

{"bugzilla": {"description": "kernel: powerpc/kasan: Fix early region not updated correctly", "id": "2347706", "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2347706"}, "csaw": false, "cvss3": {"cvss3_base_score": "7.8", "cvss3_scoring_vector": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H", "status": "draft"}, "cwe": "CWE-787", "details": ["In the Linux kernel, the following vulnerability has been resolved:\npowerpc/kasan: Fix early region not updated correctly\nThe shadow's page table is not updated when PTE_RPN_SHIFT is 24\nand PAGE_SHIFT is 12. It not only causes false positives but\nalso false negative as shown the following text.\nFix it by bringing the logic of kasan_early_shadow_page_entry here.\n1. False Positive:\n==================================================================\nBUG: KASAN: vmalloc-out-of-bounds in pcpu_alloc+0x508/0xa50\nWrite of size 16 at addr f57f3be0 by task swapper/0/1\nCPU: 0 PID: 1 Comm: swapper/0 Not tainted 5.15.0-12267-gdebe436e77c7 #1\nCall Trace:\n[c80d1c20] [c07fe7b8] dump_stack_lvl+0x4c/0x6c (unreliable)\n[c80d1c40] [c02ff668] print_address_description.constprop.0+0x88/0x300\n[c80d1c70] [c02ff45c] kasan_report+0x1ec/0x200\n[c80d1cb0] [c0300b20] kasan_check_range+0x160/0x2f0\n[c80d1cc0] [c03018a4] memset+0x34/0x90\n[c80d1ce0] [c0280108] pcpu_alloc+0x508/0xa50\n[c80d1d40] [c02fd7bc] __kmem_cache_create+0xfc/0x570\n[c80d1d70] [c0283d64] kmem_cache_create_usercopy+0x274/0x3e0\n[c80d1db0] [c2036580] init_sd+0xc4/0x1d0\n[c80d1de0] [c00044a0] do_one_initcall+0xc0/0x33c\n[c80d1eb0] [c2001624] kernel_init_freeable+0x2c8/0x384\n[c80d1ef0] [c0004b14] kernel_init+0x24/0x170\n[c80d1f10] [c001b26c] ret_from_kernel_thread+0x5c/0x64\nMemory state around the buggy address:\nf57f3a80: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8\nf57f3b00: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8\n>f57f3b80: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8\n^\nf57f3c00: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8\nf57f3c80: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8\n==================================================================\n2. False Negative (with KASAN tests):\n==================================================================\nBefore fix:\nok 45 - kmalloc_double_kzfree\n# vmalloc_oob: EXPECTATION FAILED at lib/test_kasan.c:1039\nKASAN failure expected in \"((volatile char *)area)[3100]\", but none occurred\nnot ok 46 - vmalloc_oob\nnot ok 1 - kasan\n==================================================================\nAfter fix:\nok 1 - kasan"], "name": "CVE-2021-47640", "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"}], "public_date": "2025-02-26T00:00:00Z", "references": ["https://www.cve.org/CVERecord?id=CVE-2021-47640\nhttps://nvd.nist.gov/vuln/detail/CVE-2021-47640\nhttps://lore.kernel.org/linux-cve-announce/2025022647-CVE-2021-47640-1cf1@gregkh/T"], "threat_severity": "Important"}

{}