201 lines
11 KiB
JSON
201 lines
11 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-2026-89961",
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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": "2026-09-11T19:38:34.778Z",
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"datePublished": "2026-09-16T10:32:43.921Z",
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"dateUpdated": "2026-10-19T08:55:35.034Z"
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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": "2026-10-19T08:55:35.034Z"
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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\npowerpc/mm: fix wrong addr_pfn tracking in compound vmemmap population\n\nvmemmap_populate_compound_pages() uses addr_pfn to determine the PFN\noffset within a compound page and to decide whether the current vmemmap\nslot should be populated as a head page mapping or should reuse a tail\npage mapping.\n\nHowever, addr_pfn is advanced manually in parallel with addr. The loop\nitself progresses in vmemmap address space, so each PAGE_SIZE step in addr\ncovers PAGE_SIZE / sizeof(struct page) struct page slots. Since addr_pfn\nis compared against nr_pages in data-PFN units, it should advance by the\nsame number of PFNs. The existing manual increments do not match that and\ntherefore do not reliably track the PFN corresponding to the current addr.\n\nAs a result, pfn_offset can be computed from the wrong PFN and the code\ncan make the head/tail decision for the wrong compound-page position.\n\nFix this by deriving addr_pfn directly from the current vmemmap address\ninstead of carrying it as loop state."
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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:H/A:H",
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"baseScore": 7.8,
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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 powerpc radix vmemmap_populate_compound_pages(), reached only through local ZONE_DEVICE hotplug (dev_dax_probe → devm_memremap_pages → arch_add_memory → sparse_add_section). It is not reachable from network protocols, Bluetooth, or USB.\nAC:L - Once device-DAX with compound vmemmap is mapped (2MB PMD on 4K kernels or 1GB PUD on 64K, the documented powerpc DAX configs), addr_pfn drifts on every loop iteration and the wrong head/tail mapping is deterministic; no race or attacker-uncontrollable layout is required.\nPR:L - Initial memremap requires administrator DAX setup, but on a provisioned persistent-memory or cloud POWER server an unprivileged local user with /dev/dax access can mmap the device and drive kernel use of the mis-aliased struct pages via faults and GUP without init-namespace CAP_SYS_ADMIN.\nUI:N - Exploitation needs no victim action; the attacker mmaps or faults the already-provisioned DAX device themselves. No mount, click, or hotplug by another user is required at exploit time.\nS:U - Impact is kernel struct-page aliasing and MM corruption inside the same host kernel security authority. It is not a KVM guest-to-host escape, IOMMU/DMA bypass, or sandbox boundary crossing.\nC:H - Wrong pfn_offset aliases distinct vmemmap pages so different DAX PFNs share struct-page backing; later memmap_init, faults, and GUP read corrupted flags, mapping, and compound-head fields, disclosing kernel memory via that metadata.\nI:H - The same aliases turn kernel writes (page init, folio mapping, refcount, compound head/tail linkage) into writes to the wrong struct pages, an exploitable kernel memory-corruption primitive that can hijack control flow rather than a bounded data modification.\nA:H - Mis-linked compound pages and aliased vmemmap cause kernel oops, BUG_ON, or panic when MM code walks folio heads, refcounts, or DAX fault handlers, fully denying availability of the affected POWER radix host."
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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/powerpc/mm/book3s64/radix_pgtable.c"
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],
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"versions": [
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{
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"version": "f2b79c0d79683d552369bb9a7282c1f0226fc566",
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"lessThan": "b96be860673f9fbbf12cdadb0b25fc4d6d4d207f",
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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": "f2b79c0d79683d552369bb9a7282c1f0226fc566",
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"lessThan": "e163c7184acf36ac20a248498f4a16016057ca01",
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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": "f2b79c0d79683d552369bb9a7282c1f0226fc566",
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"lessThan": "9c914b7a0bd18834505c65f22225ce22c152b2d9",
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"status": "affected",
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"versionType": "git"
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{
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"version": "f2b79c0d79683d552369bb9a7282c1f0226fc566",
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"lessThan": "7968852a7ca3ce81477ec5b4494a28d612f35a97",
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"status": "affected",
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{
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"lessThan": "89a4ae32764172468dea303eb6ae90fe6c859712",
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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/powerpc/mm/book3s64/radix_pgtable.c"
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],
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"versions": [
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{
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"version": "6.6",
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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": "6.6",
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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": "6.6.157",
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"lessThanOrEqual": "6.6.*",
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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": "6.12.110",
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"lessThanOrEqual": "6.12.*",
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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": "6.18.51",
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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": "7.2.5",
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"lessThanOrEqual": "7.2.*",
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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": "7.3",
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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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"vulnerable": true,
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"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
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"versionStartIncluding": "6.6",
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"versionEndExcluding": "6.6.157"
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"versionEndExcluding": "7.2.5"
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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": "6.6",
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"versionEndExcluding": "7.3"
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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/b96be860673f9fbbf12cdadb0b25fc4d6d4d207f"
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},
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{
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"url": "https://git.kernel.org/stable/c/e163c7184acf36ac20a248498f4a16016057ca01"
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},
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{
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"url": "https://git.kernel.org/stable/c/9c914b7a0bd18834505c65f22225ce22c152b2d9"
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},
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{
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"url": "https://git.kernel.org/stable/c/7968852a7ca3ce81477ec5b4494a28d612f35a97"
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},
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{
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"url": "https://git.kernel.org/stable/c/89a4ae32764172468dea303eb6ae90fe6c859712"
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}
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],
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"title": "powerpc/mm: fix wrong addr_pfn tracking in compound vmemmap population",
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