175 lines
9.8 KiB
JSON
175 lines
9.8 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-2026-80685",
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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": "2026-08-26T14:34:25.784Z",
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"datePublished": "2026-08-28T06:52:51.305Z",
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"dateUpdated": "2026-09-21T13:14:10.006Z"
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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": "2026-09-21T13:14:10.006Z"
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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\nmm/util: don't read __page_2 for order-1 folios in snapshot_page()\n\nsnapshot_page() currently reads __page_2 after checking nr_pages > 1, but\nit should only do so when nr_pages > 2.\n\nIf an order-1 folio is allocated at the end of a vmemmap section,\n__page_2 will not exist and reading it will cause a fault.\n\nDuring DLPAR memory remove on a 22 TB ppc64le LPAR, snapshot_page() oopsed\non the page isolation path while reading an order-1 folio's __page_2 from\nan adjacent absent section (unmapped vmemmap).\n\nFix this to avoid reading memmap that doesn't exist (e.g., a vmemmap\nhole)."
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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 - Reachable via local read(2) on /proc/kpageflags or /proc/kpagecount (kpage_read→stable_page_flags/get_kpage_count→snapshot_page); the reported production crash also occurs on the memory-hotplug page-isolation dump_page path during offline_pages/DLPAR, with no network or physical-bus entry point.\nAC:L - A container/user-namespace root can sequentially scan PFNs via /proc/kpageflags until snapshot_page hits an order-1 folio at a vmemmap section boundary; on large SPARSEMEM_VMEMMAP systems such folios exist naturally (22 TB ppc64le LPAR oops) without races or attacker-uncontrollable timing.\nPR:L - /proc/kpage* is mode 0400 (root-only); exploitation needs only namespace/container root or CAP_SYS_ADMIN in a user namespace to read host proc on typical Docker/K8s/cloud nodes—not init-namespace root; the DLPAR offline path needs admin but is not the lowest-privilege vector.\nUI:N - The attacker performs their own /proc/kpageflags reads or triggers kernel debug dumps; no separate victim action such as opening a file, mounting a filesystem, or approving a prompt is required beyond having local proc access.\nS:U - Impact is a kernel oops/panic within the host kernel security boundary; there is no VM escape, IOMMU bypass, or cross-authority resource access beyond crashing or destabilizing the shared kernel.\nC:H - snapshot_page() performs memcpy of a full struct page from foliop->__page_2 when only two pages are valid for order-1 folios, reading beyond allocated vmemmap into an unmapped hole; this out-of-bounds kernel read can expose adjacent mapped memmap bytes to the snapshot buffer on some layouts before faulting.\nI:N - The defect is a read past valid folio memmap that page-faults in kernel mode; memcpy only fills a local page_snapshot buffer and does not corrupt kernel objects, enable arbitrary writes, or provide a control-flow hijack primitive.\nA:H - Reading absent vmemmap for order-1 folios at section boundaries causes a supervisor page fault and kernel oops, as demonstrated during DLPAR memory remove on ppc64le; repeated /proc/kpageflags scanning can reliably panic or hang large-memory cloud/LPAR hosts."
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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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"mm/util.c"
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],
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"versions": [
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{
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"version": "31a31da8a6187f1e5448ec73222e01d7d3fed4aa",
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"lessThan": "9668ffe0e2a5e2399dce281620198a2e415871fc",
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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": "31a31da8a6187f1e5448ec73222e01d7d3fed4aa",
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"lessThan": "c649324571206a30949765320b91ccdb4c1722dc",
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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": "31a31da8a6187f1e5448ec73222e01d7d3fed4aa",
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"lessThan": "7441d6348c70738e9ed307510db171c7a9b3f4bf",
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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": "4117738bd42c8ab58090729daf0f8472a936f662",
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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": "6.12.111",
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"lessThan": "6.13",
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"status": "affected",
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"versionType": "semver"
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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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"mm/util.c"
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],
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"versions": [
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{
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"version": "6.15",
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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": "6.15",
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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": "6.18.44",
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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": "7.1.8",
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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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{
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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": "6.15",
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"versionEndExcluding": "6.18.44"
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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": "6.15",
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"versionEndExcluding": "7.1.8"
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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": "6.15",
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"versionEndExcluding": "7.2"
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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": "6.12.111"
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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/9668ffe0e2a5e2399dce281620198a2e415871fc"
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},
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{
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"url": "https://git.kernel.org/stable/c/c649324571206a30949765320b91ccdb4c1722dc"
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},
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{
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"url": "https://git.kernel.org/stable/c/7441d6348c70738e9ed307510db171c7a9b3f4bf"
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}
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],
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"title": "mm/util: don't read __page_2 for order-1 folios in snapshot_page()",
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"x_generator": {
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"engine": "bippy-1.2.0"
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}
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} |