159 lines
9.5 KiB
JSON
159 lines
9.5 KiB
JSON
{
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"dataType": "CVE_RECORD",
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"dataVersion": "5.2",
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"cveMetadata": {
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"cveId": "CVE-2026-68172",
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"assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
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"state": "PUBLISHED",
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"assignerShortName": "Linux",
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"dateReserved": "2026-07-30T09:28:09.372Z",
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"datePublished": "2026-08-10T11:59:41.893Z",
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"dateUpdated": "2026-08-17T05:00:12.926Z"
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},
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"containers": {
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"cna": {
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"providerMetadata": {
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"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
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"shortName": "Linux",
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"dateUpdated": "2026-08-17T05:00:12.926Z"
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},
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"descriptions": [
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{
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"lang": "en",
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"value": "In the Linux kernel, the following vulnerability has been resolved:\n\narm64: make huge_ptep_get handled unaligned addresses\n\nhuge_ptep_get() can be handed a virtual address pointing to the middle\nof a contpmd/contpte mapped hugetlb folio (examples of callers are\npagemap_hugetlb_range, page_mapped_in_vma).\n\nThe arm64 helper rewalks the pgtables in find_num_contig to answer\nwhether the huge pte we have maps a contpmd or a contpte hugetlb folio,\nand returns CONT_PMDS or CONT_PTES, so that it can collect a/d bits over\nthe contiguous ptes. We can falsely return CONT_PTES instead of\nCONT_PMDS if the addr is not aligned. On systems where CONT_PTES !=\nCONT_PMDS (meaning page size is 16K), we could collect excess A/D bit\nstate, meaning extra work for the kernel. Even worse, we may iterate\nbeyond the PTE table and dereference a garbage ptep pointer to access\nphysical memory we don't own. Since the ptep pointer is a linear map\naddress, we may run off the end of the linear map or into a hole,\ndereference a VA not mapped into the kernel pgtables and cause kernel\npanic.\n\nFix this by aligning the pmdp pointer down to a contpmd base before\nchecking equality with the passed huge pte pointer, to correctly answer\nwhether the huge pte is the base of a contpmd block."
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}
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],
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"metrics": [
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{
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"cvssV3_1": {
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"version": "3.1",
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"vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H",
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"baseScore": 7.1,
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"baseSeverity": "HIGH"
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},
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"scenarios": [
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{
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"lang": "en",
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"value": "AV:L - The bug is in arm64 huge_ptep_get(), reached only from local kernel entry points such as the mincore(2) syscall, hugetlb page-fault handling, and reading /proc/self/pagemap or smaps; there is no network, adjacent-radio, or physical-device path to this code.\nAC:L - On affected arm64 16K kernels with HugeTLB, an unprivileged process can mmap a contiguous-PMD (1G) hugetlb mapping and reliably trigger the bug via mincore() or a write fault at a page-aligned but contpmd-unaligned virtual address; no race or victim state outside attacker control is required.\nPR:L - Exploitation requires only a local unprivileged user who can invoke syscalls and access its own address space (/proc/self/pagemap and mincore on self mappings); no real root, CAP_SYS_ADMIN, or cross-user ptrace privileges are needed.\nUI:N - Triggering the flaw needs no action from another user or administrator beyond the attacker running its own syscalls against hugetlb mappings it created; no mount, file-open, or click-through by a victim is required.\nS:U - Impact is a kernel oops/panic and possible kernel page-table reads within the same kernel security authority; it does not cross VM, container, or IOMMU boundaries to compromise a separate security domain.\nC:H - Misclassifying a contpmd mapping causes huge_ptep_get() to iterate CONT_PTES times over advancing ptep pointers, reading PTE values beyond the valid table and potentially disclosing adjacent kernel page-table/physical-address data before dereferencing an unmapped linear-map address.\nI:N - The defective path only performs out-of-bounds PTE reads via __ptep_get(); it does not corrupt or write memory, modify page tables, or achieve code execution—only incorrect aggregation of accessed/dirty bits and eventual fatal dereference.\nA:H - Iteration can advance ptep into unmapped linear-map holes or past valid kernel mappings, causing an unhandled kernel page fault and system panic/oops, yielding complete loss of kernel availability on affected arm64 16K HugeTLB systems."
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}
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]
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}
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],
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"affected": [
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{
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"product": "Linux",
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"vendor": "Linux",
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"defaultStatus": "unaffected",
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"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
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"programFiles": [
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"arch/arm64/mm/hugetlbpage.c"
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],
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"versions": [
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{
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"version": "29cb80519689706387bde47000dbb2ed91143063",
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"lessThan": "9cd4b1a52eff330798d668c1775f8bc450776280",
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"status": "affected",
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"versionType": "git"
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},
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{
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"version": "29cb80519689706387bde47000dbb2ed91143063",
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"lessThan": "f3530aec26563f4d483ff31402392961362e9bc6",
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"status": "affected",
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"versionType": "git"
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},
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{
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"version": "29cb80519689706387bde47000dbb2ed91143063",
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"lessThan": "f73a8edc2ccc6ec72c37d5c578e7592d2e1f9922",
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"status": "affected",
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"versionType": "git"
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}
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]
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},
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{
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"product": "Linux",
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"vendor": "Linux",
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"defaultStatus": "affected",
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"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
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"programFiles": [
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"arch/arm64/mm/hugetlbpage.c"
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],
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"versions": [
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{
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"version": "6.16",
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"status": "affected"
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},
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{
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"version": "0",
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"lessThan": "6.16",
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"status": "unaffected",
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"versionType": "semver"
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},
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{
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"version": "6.18.42",
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"lessThanOrEqual": "6.18.*",
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"status": "unaffected",
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"versionType": "semver"
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},
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{
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"version": "7.1.6",
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"lessThanOrEqual": "7.1.*",
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"status": "unaffected",
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"versionType": "semver"
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},
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{
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"version": "7.2",
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"lessThanOrEqual": "*",
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"status": "unaffected",
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"versionType": "original_commit_for_fix"
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}
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]
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}
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],
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"cpeApplicability": [
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{
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"nodes": [
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"operator": "OR",
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"negate": false,
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"cpeMatch": [
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{
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"vulnerable": true,
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"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
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"versionStartIncluding": "6.16",
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"versionEndExcluding": "6.18.42"
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},
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{
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"vulnerable": true,
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"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
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"versionStartIncluding": "6.16",
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"versionEndExcluding": "7.1.6"
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},
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{
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"vulnerable": true,
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"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
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"versionStartIncluding": "6.16",
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"versionEndExcluding": "7.2"
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}
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]
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}
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]
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}
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],
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"references": [
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{
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"url": "https://git.kernel.org/stable/c/9cd4b1a52eff330798d668c1775f8bc450776280"
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},
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{
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"url": "https://git.kernel.org/stable/c/f3530aec26563f4d483ff31402392961362e9bc6"
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},
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{
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"url": "https://git.kernel.org/stable/c/f73a8edc2ccc6ec72c37d5c578e7592d2e1f9922"
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}
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],
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"title": "arm64: make huge_ptep_get handled unaligned addresses",
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} |