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vuln-cve/data/2026/93xxx/CVE-2026-93237.json
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{
"dataType": "CVE_RECORD",
"dataVersion": "5.2",
"cveMetadata": {
"cveId": "CVE-2026-93237",
"assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"state": "PUBLISHED",
"assignerShortName": "Linux",
"dateReserved": "2026-09-17T16:02:15.095Z",
"datePublished": "2026-09-24T15:33:51.702Z",
"dateUpdated": "2026-10-19T09:07:48.863Z"
},
"containers": {
"cna": {
"providerMetadata": {
"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"shortName": "Linux",
"dateUpdated": "2026-10-19T09:07:48.863Z"
},
"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nLoongArch: Add DIRECT_MAP_PHYSMEM_END definition\n\nget_free_mem_region() and mhp_get_pluggable_range() bound their search\nto DIRECT_MAP_PHYSMEM_END. LoongArch does not define it, so the fallback\nin include/linux/mm.h applies: under CONFIG_SPARSEMEM_VMEMMAP it is\n(1ULL << MAX_PHYSMEM_BITS) - 1, a compile-time constant that does not\nadapt to the CPU's physical address space bits (cpu_pabits, probed from\nCPUCFG1).\n\nThe vmemmap window only covers physical space below 2^(cpu_pabits+1)\n(i.e. VMEMMAP_SIZE), so on CPUs with fewer physical address bits than\nMAX_PHYSMEM_BITS the fallback allows get_free_mem_region() to return\na ZONE_DEVICE region outside the vmemmap window; vmemmap_populate() then\nwraps the memmap range around and maps it into low memory, silently\ncorrupting the page tables. The same search also picked the top-of-\naddress-space region that crashed memmap_init_zone_device() with amdkfd\non Loongson-3C6000 in 6.16 [1]; the commit 2969b42c8f99 (\"LoongArch/mm:\nalign vmemmap to maximal folio size\") keeps that region in bounds on\ncurrent Loongson-3C6000 configs, but CPUs with smaller cpu_pabits (e.g.\nthe Loongson-2K series) are still affected.\n\nDefine DIRECT_MAP_PHYSMEM_END as the vmemmap-covered physical range,\n(1ULL << (cpu_pabits + 1)) - 1, capped at (1ULL << MAX_PHYSMEM_BITS) - 1\nunder CONFIG_SPARSEMEM, similar to the commit f3336b48cf9d (\"riscv: mm:\nDefine DIRECT_MAP_PHYSMEM_END\").\n\n[1] https://lore.kernel.org/amd-gfx/20250814032153.227285-1-jeffbai@aosc.io/"
}
],
"metrics": [
{
"cvssV3_1": {
"version": "3.1",
"vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
"baseScore": 7.8,
"baseSeverity": "HIGH"
},
"scenarios": [
{
"lang": "en",
"value": "AV:L - The missing DIRECT_MAP_PHYSMEM_END is consumed by gfr_start() inside get_free_mem_region() when kgd2kfd_init_zone_device() calls devm_request_free_mem_region(&iomem_resource) from amdgpu device init (HSA_AMD depends on LOONGARCH && 64BIT); that is local PCI-probe HMM setup, not a remote protocol message.\nAC:L - With GFR_DESCENDING, gfr_start() always starts at min(iomem_resource.end, the mm.h fallback (1ULL<<MAX_PHYSMEM_BITS)-1) minus size, so on a CPU with cpu_pabits+1 below 48 the first ZONE_DEVICE slot is above VMEMMAP_SIZE and vmemmap_populate() wraps with no race or victim-owned device fault.\nPR:L - amdgpu PCI probe runs kgd2kfd_init_zone_device()→devm_memremap_pages() with no capable() check from userspace; after that wrap the unprivileged local account on a typical ROCm/desktop LoongArch host (render group, /dev/kfd with kfd_open() likewise ungated) shares the corrupted init_mm without init-namespace root.\nUI:N - amdgpu_device init itself calls kgd2kfd_init_zone_device() and then pagemap_range()→add_pages()→vmemmap_populate() on PCI bind; no victim must mount media, open a file, or click, and any NOUVEAU_SVM_BIND the attacker issues is on their own DRM fd.\nS:U - LoongArch vmemmap_populate() (vmemmap_set_pmd/vmemmap_populate_hugepages) writes PTEs via pgd_offset_k() into init_mm for the wrapped pfn_to_page() VA, which is host kernel MM corruption, not a KVM guest-to-host escape or IOMMU/DMA bypass.\nC:H - __populate_section_memmap() sets start to (unsigned long)pfn_to_page() of the out-of-window ZONE_DEVICE PFN, so vmemmap_populate() maps struct-page backing over low kernel VAs; memmap_init_zone_device() then stores page->pgmap and flags through that alias, disclosing kernel pointers and data those VAs previously mapped.\nI:H - vmemmap_set_pmd() installs PAGE_KERNEL PMDs at the wrapped address and memmap_init_zone_device() writes struct-page fields through pfn_to_page() into that alias, an unconstrained kernel page-table and metadata write rather than a bounded data tweak.\nA:H - The same top-of-address-space region already crashed memmap_init_zone_device() with amdkfd on Loongson-3C6000, and on smaller cpu_pabits the wrap leaves init_mm PTEs pointing at the wrong physical pages so later pfn_to_page() walks oops or panic the host."
}
]
}
],
"affected": [
{
"product": "Linux",
"vendor": "Linux",
"defaultStatus": "unaffected",
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"programFiles": [
"arch/loongarch/include/asm/pgtable.h"
],
"versions": [
{
"version": "7b09f5af01ede480cbe7abcb281cf17550a46ff5",
"lessThan": "ab275a23b4d9f04ca6c2f5f6a3246194e045a761",
"status": "affected",
"versionType": "git"
},
{
"version": "7b09f5af01ede480cbe7abcb281cf17550a46ff5",
"lessThan": "55e18311c705cceef6c34d522ea387b1f0069bab",
"status": "affected",
"versionType": "git"
},
{
"version": "7b09f5af01ede480cbe7abcb281cf17550a46ff5",
"lessThan": "2677f97a67fdbc62a82ce1faa67791f54451d36f",
"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/loongarch/include/asm/pgtable.h"
],
"versions": [
{
"version": "6.2",
"status": "affected"
},
{
"version": "0",
"lessThan": "6.2",
"status": "unaffected",
"versionType": "semver"
},
{
"version": "6.18.51",
"lessThanOrEqual": "6.18.*",
"status": "unaffected",
"versionType": "semver"
},
{
"version": "7.2.5",
"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": "6.2",
"versionEndExcluding": "6.18.51"
},
{
"vulnerable": true,
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionStartIncluding": "6.2",
"versionEndExcluding": "7.2.5"
},
{
"vulnerable": true,
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionStartIncluding": "6.2",
"versionEndExcluding": "7.3"
}
]
}
]
}
],
"references": [
{
"url": "https://git.kernel.org/stable/c/ab275a23b4d9f04ca6c2f5f6a3246194e045a761"
},
{
"url": "https://git.kernel.org/stable/c/55e18311c705cceef6c34d522ea387b1f0069bab"
},
{
"url": "https://git.kernel.org/stable/c/2677f97a67fdbc62a82ce1faa67791f54451d36f"
}
],
"title": "LoongArch: Add DIRECT_MAP_PHYSMEM_END definition",
"x_generator": {
"engine": "bippy-1.2.0"
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}
}