185 lines
10 KiB
JSON
185 lines
10 KiB
JSON
{
|
|
"dataType": "CVE_RECORD",
|
|
"dataVersion": "5.2",
|
|
"cveMetadata": {
|
|
"cveId": "CVE-2026-97945",
|
|
"assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
|
|
"state": "PUBLISHED",
|
|
"assignerShortName": "Linux",
|
|
"dateReserved": "2026-09-25T10:18:58.204Z",
|
|
"datePublished": "2026-09-25T10:22:55.981Z",
|
|
"dateUpdated": "2026-10-19T09:11:11.655Z"
|
|
},
|
|
"containers": {
|
|
"cna": {
|
|
"providerMetadata": {
|
|
"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
|
|
"shortName": "Linux",
|
|
"dateUpdated": "2026-10-19T09:11:11.655Z"
|
|
},
|
|
"descriptions": [
|
|
{
|
|
"lang": "en",
|
|
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nx86/mm: Fix user-space data loss with MADV_FREE and THP\n\nSome of users of Polars (a data analytics library) have lost production\ndata from this bug. They seem to have just the right combination of\nhuge pages, MADV_FREE and heavy reclaim pressure.\n\npmd_modify() masks the old value with (_HPAGE_CHG_MASK & ~_PAGE_DIRTY),\nsilently discarding the hardware dirty bit. The subsequent\npmd_mksaveddirty() call is supposed to transfer _PAGE_DIRTY into\n_PAGE_SAVED_DIRTY when write-protecting, but the dirty bit was already\nstripped from the value, so there is nothing left to transfer.\n\nContrast with pte_modify(), which keeps _PAGE_DIRTY_BITS in its mask,\nand pud_modify(), which keeps _HPAGE_CHG_MASK untouched: pmd_modify()\nis the odd one out. Any pmd_modify() on a writable, dirty PMD loses\nthe dirty state.\n\nOne visible consequence is data loss with MADV_FREE on PMD-mapped THP:\n\n memset(buf, 0x5A, size); // PMD-mapped THP, PMD dirty\n madvise(buf, size, MADV_FREE); // PMD cleaned but left writable,\n // folio marked lazyfree\n memset(buf, 0x5A, size); // hardware sets _PAGE_DIRTY again\n mprotect(buf, size, PROT_READ); // pmd_modify() drops the dirty bit\n mprotect(buf, size, PROT_READ|PROT_WRITE);\n // ... memory pressure ...\n\nReclaim (e.g. under memcg pressure) then finds the lazyfree folio with\nno dirty bit set anywhere and frees it in\n__discard_anon_folio_pmd_locked(), even though the data was rewritten\nafter MADV_FREE; subsequent reads fault in fresh zero pages. NUMA\nhinting alone can trigger the same loss, as do_huge_pmd_numa_page()\nrestores the PMD through pmd_modify() as well.\n\nPMD-mapped file THPs are affected too: mprotect()/NUMA hinting dropping\nthe dirty bit means rewritten data is never written back.\n\nFix it by keeping _PAGE_DIRTY in the preserved mask, exactly like\npte_modify() and pud_modify() do. The existing\npmd_mksaveddirty()/pmd_clear_saveddirty() pair then performs the\nhardware-dirty <-> saved-dirty transition based on the write bit,\npreserving the shadow-stack encoding rules."
|
|
}
|
|
],
|
|
"affected": [
|
|
{
|
|
"product": "Linux",
|
|
"vendor": "Linux",
|
|
"defaultStatus": "unaffected",
|
|
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
|
|
"programFiles": [
|
|
"arch/x86/include/asm/pgtable.h"
|
|
],
|
|
"versions": [
|
|
{
|
|
"version": "bb3aadf7d446aaf22c725b274e2c194ac5cb2111",
|
|
"lessThan": "b5dec6dfb593d81fec15ba43c4fe5d58f10a49a2",
|
|
"status": "affected",
|
|
"versionType": "git"
|
|
},
|
|
{
|
|
"version": "bb3aadf7d446aaf22c725b274e2c194ac5cb2111",
|
|
"lessThan": "e4d569fe2f436a9b58c048fefabf56eab68c1b7e",
|
|
"status": "affected",
|
|
"versionType": "git"
|
|
},
|
|
{
|
|
"version": "bb3aadf7d446aaf22c725b274e2c194ac5cb2111",
|
|
"lessThan": "55ddbc2ca6d5db64d44c3fb8f8705b4d39eb30b7",
|
|
"status": "affected",
|
|
"versionType": "git"
|
|
},
|
|
{
|
|
"version": "bb3aadf7d446aaf22c725b274e2c194ac5cb2111",
|
|
"lessThan": "a5ad97cbcfcec31430268441c10eedde73200177",
|
|
"status": "affected",
|
|
"versionType": "git"
|
|
},
|
|
{
|
|
"version": "bb3aadf7d446aaf22c725b274e2c194ac5cb2111",
|
|
"lessThan": "f7491d7c81db0e7c304a7bd757a76d2fbeaff80e",
|
|
"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/x86/include/asm/pgtable.h"
|
|
],
|
|
"versions": [
|
|
{
|
|
"version": "6.6",
|
|
"status": "affected"
|
|
},
|
|
{
|
|
"version": "0",
|
|
"lessThan": "6.6",
|
|
"status": "unaffected",
|
|
"versionType": "semver"
|
|
},
|
|
{
|
|
"version": "6.6.158",
|
|
"lessThanOrEqual": "6.6.*",
|
|
"status": "unaffected",
|
|
"versionType": "semver"
|
|
},
|
|
{
|
|
"version": "6.12.111",
|
|
"lessThanOrEqual": "6.12.*",
|
|
"status": "unaffected",
|
|
"versionType": "semver"
|
|
},
|
|
{
|
|
"version": "6.18.53",
|
|
"lessThanOrEqual": "6.18.*",
|
|
"status": "unaffected",
|
|
"versionType": "semver"
|
|
},
|
|
{
|
|
"version": "7.2.7",
|
|
"lessThanOrEqual": "7.2.*",
|
|
"status": "unaffected",
|
|
"versionType": "semver"
|
|
},
|
|
{
|
|
"version": "7.3",
|
|
"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": "6.6",
|
|
"versionEndExcluding": "6.6.158"
|
|
},
|
|
{
|
|
"vulnerable": true,
|
|
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
|
|
"versionStartIncluding": "6.6",
|
|
"versionEndExcluding": "6.12.111"
|
|
},
|
|
{
|
|
"vulnerable": true,
|
|
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
|
|
"versionStartIncluding": "6.6",
|
|
"versionEndExcluding": "6.18.53"
|
|
},
|
|
{
|
|
"vulnerable": true,
|
|
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
|
|
"versionStartIncluding": "6.6",
|
|
"versionEndExcluding": "7.2.7"
|
|
},
|
|
{
|
|
"vulnerable": true,
|
|
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
|
|
"versionStartIncluding": "6.6",
|
|
"versionEndExcluding": "7.3"
|
|
}
|
|
]
|
|
}
|
|
]
|
|
}
|
|
],
|
|
"references": [
|
|
{
|
|
"url": "https://git.kernel.org/stable/c/b5dec6dfb593d81fec15ba43c4fe5d58f10a49a2"
|
|
},
|
|
{
|
|
"url": "https://git.kernel.org/stable/c/e4d569fe2f436a9b58c048fefabf56eab68c1b7e"
|
|
},
|
|
{
|
|
"url": "https://git.kernel.org/stable/c/55ddbc2ca6d5db64d44c3fb8f8705b4d39eb30b7"
|
|
},
|
|
{
|
|
"url": "https://git.kernel.org/stable/c/a5ad97cbcfcec31430268441c10eedde73200177"
|
|
},
|
|
{
|
|
"url": "https://git.kernel.org/stable/c/f7491d7c81db0e7c304a7bd757a76d2fbeaff80e"
|
|
}
|
|
],
|
|
"title": "x86/mm: Fix user-space data loss with MADV_FREE and THP",
|
|
"x_generator": {
|
|
"engine": "bippy-1.2.0"
|
|
}
|
|
}
|
|
}
|
|
} |