138 lines
10 KiB
JSON
138 lines
10 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-2026-80682",
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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": "2026-08-28T06:52:49.498Z",
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"dateUpdated": "2026-08-29T06:22:09.064Z"
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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": "2026-08-29T06:22:09.064Z"
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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\nriscv/mm: use physical alignment for vmemmap_start_pfn\n\nRISC-V computes vmemmap_start_pfn by rounding phys_ram_base down to\nVMEMMAP_ADDR_ALIGN. That alignment must therefore be expressed in the\nphysical-address domain.\n\nCommit 476849b0fba4 (\"riscv/mm: align vmemmap to maximal folio size\")\nattempted to account for the maximal folio alignment by feeding\nMAX_FOLIO_VMEMMAP_ALIGN directly into VMEMMAP_ADDR_ALIGN. However,\nMAX_FOLIO_VMEMMAP_ALIGN is measured in bytes of struct page storage,\nwhereas VMEMMAP_ADDR_ALIGN is used to align a physical address.\n\nThe mask-based compound_info encoding requires pfn_to_page(0) to be\nnaturally aligned to MAX_FOLIO_VMEMMAP_ALIGN. Commit 9f94db4c7eaa\n(\"mm/sparse: check memmap alignment for compound_info_has_mask()\") added a\ncheck for that requirement and exposed the unit mismatch on systems such\nas QEMU virt, where the DRAM base is not aligned to MAX_FOLIO_NR_PAGES *\nPAGE_SIZE.\n\nHere is the log:\n[ 0.000000][ C0] ------------[ cut here ]------------\n[ 0.000000][ C0] WARNING: mm/sparse.c:365 at sparse_init+0x58a/0x6fe, CPU#0: swapper/0\n[ 0.000000][ C0] Modules linked in:\n[ 0.000000][ C0] CPU: 0 UID: 0 PID: 0 Comm: swapper Not tainted 7.2.0-rc3-g1d8304bdd65f #2 PREEMPT \n[ 0.000000][ C0] Hardware name: riscv-virtio,qemu (DT)\n[ 0.000000][ C0] epc : sparse_init+0x58a/0x6fe\n[ 0.000000][ C0] ra : sparse_init+0x58a/0x6fe\n[ 0.000000][ C0] epc : ffffffff86851c88 ra : ffffffff86851c88 sp : ffffffff88807a30\n[ 0.000000][ C0] gp : ffffffff8a3bf240 tp : ffffffff88842080 t0 : ff600000ffab6000\n[ 0.000000][ C0] t1 : 000000017fab6000 t2 : 65203a6573726363 s0 : ffffffff88807bc0\n[ 0.000000][ C0] s1 : 000000000e000000 a0 : 0000000000000007 a1 : 0000000000000000\n[ 0.000000][ C0] a2 : 0000000000000002 a3 : ffffffff86851c88 a4 : 0000000000000000\n[ 0.000000][ C0] a5 : ffffffff88843080 a6 : 0000000000000003 a7 : 0000000000000000\n[ 0.000000][ C0] s2 : ff60000000000000 s3 : 0040000000000000 s4 : 0004000000000000\n[ 0.000000][ C0] s5 : ffffffff8a4d92e0 s6 : ff600000ffab55e0 s7 : ffffffff88384d00\n[ 0.000000][ C0] s8 : 0000000000000003 s9 : ffffffff88384cc1 s10: ffffffff88384cc0\n[ 0.000000][ C0] s11: ffffffff8a4daae0 t3 : ffffffff915e8b20 t4 : ffffffff915e8b20\n[ 0.000000][ C0] t5 : ffffffff915e8b20 t6 : ffffffff915e8bc8 ssp : 0000000000000000\n[ 0.000000][ C0] status: 0000000200000100 badaddr: ffffffff86851c88 cause: 0000000000000003\n[ 0.000000][ C0] [<ffffffff86851c88>] sparse_init+0x58a/0x6fe\n[ 0.000000][ C0] [<ffffffff8683d396>] mm_core_init_early+0x116/0x1e30\n[ 0.000000][ C0] [<ffffffff86801edc>] start_kernel+0xd2/0x848\n\nConvert MAX_FOLIO_VMEMMAP_ALIGN to the equivalent physical alignment\nbefore using it in VMEMMAP_ADDR_ALIGN. This keeps the existing\nround_down() logic while making the resulting vmemmap base satisfy the\nmask-alignment requirement."
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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 flaw is set during early boot in arch/riscv/mm/init.c setup_bootmem()/sparse_init(), and runtime impact is reached through local memory-management syscalls (mmap, page faults, compound folio allocation) invoking compound_head(); no network, adjacent-network, or remote protocol path exists.\nAC:L - On affected RISC-V 64 kernels with HUGETLB/HVO enabled (RISC-V defconfig) and DRAM bases such as QEMU virt where phys_ram_base is not aligned to MAX_FOLIO_NR_PAGES*PAGE_SIZE, the wrong vmemmap_start_pfn and misaligned pfn_to_page(0) occur deterministically every boot without races or attacker-uncontrollable layout.\nPR:L - The broken vmemmap alignment is established automatically at boot before any credentials exist; once running, an unprivileged local user can trigger compound folio allocation and freeing (anonymous mmap, THP, hugetlbfs) that exercise mask-based compound_head() with no capability or namespace gate.\nUI:N - No victim interaction is required beyond normal operation of an already-affected system; the attacker does not need another user to mount filesystems, open devices, or perform discretionary actions to reach the broken compound-page paths.\nS:U - Impact is kernel memory and page-metadata corruption within the host kernel security authority; it does not cross a VM, hypervisor, IOMMU/DMA, or sandbox boundary into a separate security domain.\nC:H - Misaligned pfn_to_page(0) breaks compound_info mask decoding so compound_head() can map tail struct pages to incorrect heads, enabling out-of-bounds reads of adjacent kernel page metadata and folio contents through routine MM operations (get_user_pages, compaction, isolation).\nI:H - Resolving the wrong compound head corrupts folio refcount, mapping, and LRU state and directs kernel read/write operations to unintended physical pages, providing a defensible arbitrary kernel-memory corruption primitive leveragable for privilege escalation.\nA:H - Incorrect compound_head() resolution can oops or panic the kernel during page isolation, compaction, THP, hugetlb, and I/O pin paths; sparse_init() VM_WARN_ON_ONCE on standard QEMU virt confirms the alignment violation is real on common RISC-V deployments."
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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/riscv/mm/init.c"
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],
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"versions": [
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{
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"version": "476849b0fba4450f5adf22196bcff9c24c673bc4",
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"lessThan": "11ad86830a78ea4e1942afc73c10e4ca8e69e03f",
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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": "476849b0fba4450f5adf22196bcff9c24c673bc4",
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"lessThan": "45ebe4540817cb540a59e4dc04014ac5dddc9990",
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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/riscv/mm/init.c"
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],
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"versions": [
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{
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"version": "7.1",
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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": "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": "7.1.8",
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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": "7.1",
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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": "7.1",
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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/11ad86830a78ea4e1942afc73c10e4ca8e69e03f"
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},
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{
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"url": "https://git.kernel.org/stable/c/45ebe4540817cb540a59e4dc04014ac5dddc9990"
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}
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],
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"title": "riscv/mm: use physical alignment for vmemmap_start_pfn",
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"x_generator": {
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"engine": "bippy-1.2.0"
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}
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}
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}
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} |