{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2026-80685", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-08-26T14:34:25.784Z", "datePublished": "2026-08-28T06:52:51.305Z", "dateUpdated": "2026-09-21T13:14:10.006Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-09-21T13:14:10.006Z" }, "descriptions": [ { "lang": "en", "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)." } ], "metrics": [ { "cvssV3_1": { "version": "3.1", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H", "baseScore": 7.1, "baseSeverity": "HIGH" }, "scenarios": [ { "lang": "en", "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." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "mm/util.c" ], "versions": [ { "version": "31a31da8a6187f1e5448ec73222e01d7d3fed4aa", "lessThan": "9668ffe0e2a5e2399dce281620198a2e415871fc", "status": "affected", "versionType": "git" }, { "version": "31a31da8a6187f1e5448ec73222e01d7d3fed4aa", "lessThan": "c649324571206a30949765320b91ccdb4c1722dc", "status": "affected", "versionType": "git" }, { "version": "31a31da8a6187f1e5448ec73222e01d7d3fed4aa", "lessThan": "7441d6348c70738e9ed307510db171c7a9b3f4bf", "status": "affected", "versionType": "git" }, { "version": "4117738bd42c8ab58090729daf0f8472a936f662", "status": "affected", "versionType": "git" }, { "version": "6.12.111", "lessThan": "6.13", "status": "affected", "versionType": "semver" } ] }, { "product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "mm/util.c" ], "versions": [ { "version": "6.15", "status": "affected" }, { "version": "0", "lessThan": "6.15", "status": "unaffected", "versionType": "semver" }, { "version": "6.18.44", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.1.8", "lessThanOrEqual": "7.1.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.2", "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": "6.15", "versionEndExcluding": "6.18.44" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.15", "versionEndExcluding": "7.1.8" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.15", "versionEndExcluding": "7.2" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.12.111" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/9668ffe0e2a5e2399dce281620198a2e415871fc" }, { "url": "https://git.kernel.org/stable/c/c649324571206a30949765320b91ccdb4c1722dc" }, { "url": "https://git.kernel.org/stable/c/7441d6348c70738e9ed307510db171c7a9b3f4bf" } ], "title": "mm/util: don't read __page_2 for order-1 folios in snapshot_page()", "x_generator": { "engine": "bippy-1.2.0" } } } }