CVE-2026-80682 (GCVE-0-2026-80682)

Vulnerability from cvelistv5 – Published: 2026-08-28 06:52 – Updated: 2026-08-29 06:22
VLAI
Title
riscv/mm: use physical alignment for vmemmap_start_pfn
Summary
In the Linux kernel, the following vulnerability has been resolved: riscv/mm: use physical alignment for vmemmap_start_pfn RISC-V computes vmemmap_start_pfn by rounding phys_ram_base down to VMEMMAP_ADDR_ALIGN. That alignment must therefore be expressed in the physical-address domain. Commit 476849b0fba4 ("riscv/mm: align vmemmap to maximal folio size") attempted to account for the maximal folio alignment by feeding MAX_FOLIO_VMEMMAP_ALIGN directly into VMEMMAP_ADDR_ALIGN. However, MAX_FOLIO_VMEMMAP_ALIGN is measured in bytes of struct page storage, whereas VMEMMAP_ADDR_ALIGN is used to align a physical address. The mask-based compound_info encoding requires pfn_to_page(0) to be naturally aligned to MAX_FOLIO_VMEMMAP_ALIGN. Commit 9f94db4c7eaa ("mm/sparse: check memmap alignment for compound_info_has_mask()") added a check for that requirement and exposed the unit mismatch on systems such as QEMU virt, where the DRAM base is not aligned to MAX_FOLIO_NR_PAGES * PAGE_SIZE. Here is the log: [ 0.000000][ C0] ------------[ cut here ]------------ [ 0.000000][ C0] WARNING: mm/sparse.c:365 at sparse_init+0x58a/0x6fe, CPU#0: swapper/0 [ 0.000000][ C0] Modules linked in: [ 0.000000][ C0] CPU: 0 UID: 0 PID: 0 Comm: swapper Not tainted 7.2.0-rc3-g1d8304bdd65f #2 PREEMPT [ 0.000000][ C0] Hardware name: riscv-virtio,qemu (DT) [ 0.000000][ C0] epc : sparse_init+0x58a/0x6fe [ 0.000000][ C0] ra : sparse_init+0x58a/0x6fe [ 0.000000][ C0] epc : ffffffff86851c88 ra : ffffffff86851c88 sp : ffffffff88807a30 [ 0.000000][ C0] gp : ffffffff8a3bf240 tp : ffffffff88842080 t0 : ff600000ffab6000 [ 0.000000][ C0] t1 : 000000017fab6000 t2 : 65203a6573726363 s0 : ffffffff88807bc0 [ 0.000000][ C0] s1 : 000000000e000000 a0 : 0000000000000007 a1 : 0000000000000000 [ 0.000000][ C0] a2 : 0000000000000002 a3 : ffffffff86851c88 a4 : 0000000000000000 [ 0.000000][ C0] a5 : ffffffff88843080 a6 : 0000000000000003 a7 : 0000000000000000 [ 0.000000][ C0] s2 : ff60000000000000 s3 : 0040000000000000 s4 : 0004000000000000 [ 0.000000][ C0] s5 : ffffffff8a4d92e0 s6 : ff600000ffab55e0 s7 : ffffffff88384d00 [ 0.000000][ C0] s8 : 0000000000000003 s9 : ffffffff88384cc1 s10: ffffffff88384cc0 [ 0.000000][ C0] s11: ffffffff8a4daae0 t3 : ffffffff915e8b20 t4 : ffffffff915e8b20 [ 0.000000][ C0] t5 : ffffffff915e8b20 t6 : ffffffff915e8bc8 ssp : 0000000000000000 [ 0.000000][ C0] status: 0000000200000100 badaddr: ffffffff86851c88 cause: 0000000000000003 [ 0.000000][ C0] [<ffffffff86851c88>] sparse_init+0x58a/0x6fe [ 0.000000][ C0] [<ffffffff8683d396>] mm_core_init_early+0x116/0x1e30 [ 0.000000][ C0] [<ffffffff86801edc>] start_kernel+0xd2/0x848 Convert MAX_FOLIO_VMEMMAP_ALIGN to the equivalent physical alignment before using it in VMEMMAP_ADDR_ALIGN. This keeps the existing round_down() logic while making the resulting vmemmap base satisfy the mask-alignment requirement.
Severity
7.8 (High)
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Assigner
References
Impacted products
Vendor Product Version CPE status
Linux Linux Affected: 476849b0fba4450f5adf22196bcff9c24c673bc4 , < 11ad86830a78ea4e1942afc73c10e4ca8e69e03f (git)
Affected: 476849b0fba4450f5adf22196bcff9c24c673bc4 , < 45ebe4540817cb540a59e4dc04014ac5dddc9990 (git)
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Linux Linux Affected: 7.1
Unaffected: 0 , < 7.1 (semver)
Unaffected: 7.1.8 , ≤ 7.1.* (semver)
Unaffected: 7.2 , ≤ * (original_commit_for_fix)
guessed Create a notification for this product.
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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "arch/riscv/mm/init.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "11ad86830a78ea4e1942afc73c10e4ca8e69e03f",
              "status": "affected",
              "version": "476849b0fba4450f5adf22196bcff9c24c673bc4",
              "versionType": "git"
            },
            {
              "lessThan": "45ebe4540817cb540a59e4dc04014ac5dddc9990",
              "status": "affected",
              "version": "476849b0fba4450f5adf22196bcff9c24c673bc4",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "arch/riscv/mm/init.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "7.1"
            },
            {
              "lessThan": "7.1",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.1.*",
              "status": "unaffected",
              "version": "7.1.8",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.2",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.1.8",
                  "versionStartIncluding": "7.1",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.2",
                  "versionStartIncluding": "7.1",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "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] [\u003cffffffff86851c88\u003e] sparse_init+0x58a/0x6fe\n[    0.000000][    C0] [\u003cffffffff8683d396\u003e] mm_core_init_early+0x116/0x1e30\n[    0.000000][    C0] [\u003cffffffff86801edc\u003e] 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."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "baseScore": 7.8,
            "baseSeverity": "HIGH",
            "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
            "version": "3.1"
          },
          "scenarios": [
            {
              "lang": "en",
              "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."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-29T06:22:09.064Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/11ad86830a78ea4e1942afc73c10e4ca8e69e03f"
        },
        {
          "url": "https://git.kernel.org/stable/c/45ebe4540817cb540a59e4dc04014ac5dddc9990"
        }
      ],
      "title": "riscv/mm: use physical alignment for vmemmap_start_pfn",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-80682",
    "datePublished": "2026-08-28T06:52:49.498Z",
    "dateReserved": "2026-08-26T14:34:25.784Z",
    "dateUpdated": "2026-08-29T06:22:09.064Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "epss": {
      "cve": "CVE-2026-80682",
      "date": "2026-09-01",
      "epss": "0.00134",
      "percentile": "0.03168"
    },
    "nvd": "{\"cve\":{\"id\":\"CVE-2026-80682\",\"sourceIdentifier\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"published\":\"2026-08-28T08:16:53.607\",\"lastModified\":\"2026-08-29T07:16:50.703\",\"vulnStatus\":\"Received\",\"cveTags\":[],\"descriptions\":[{\"lang\":\"en\",\"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] [\u003cffffffff86851c88\u003e] sparse_init+0x58a/0x6fe\\n[    0.000000][    C0] [\u003cffffffff8683d396\u003e] mm_core_init_early+0x116/0x1e30\\n[    0.000000][    C0] [\u003cffffffff86801edc\u003e] 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.\"}],\"affected\":[{\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"affectedData\":[{\"vendor\":\"Linux\",\"product\":\"Linux\",\"defaultStatus\":\"unaffected\",\"programFiles\":[\"arch/riscv/mm/init.c\"],\"repo\":\"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\"versions\":[{\"version\":\"476849b0fba4450f5adf22196bcff9c24c673bc4\",\"lessThan\":\"11ad86830a78ea4e1942afc73c10e4ca8e69e03f\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"476849b0fba4450f5adf22196bcff9c24c673bc4\",\"lessThan\":\"45ebe4540817cb540a59e4dc04014ac5dddc9990\",\"versionType\":\"git\",\"status\":\"affected\"}]},{\"vendor\":\"Linux\",\"product\":\"Linux\",\"defaultStatus\":\"affected\",\"programFiles\":[\"arch/riscv/mm/init.c\"],\"repo\":\"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\"versions\":[{\"version\":\"7.1\",\"status\":\"affected\"},{\"version\":\"0\",\"lessThan\":\"7.1\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"7.1.8\",\"lessThanOrEqual\":\"7.1.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"7.2\",\"lessThanOrEqual\":\"*\",\"versionType\":\"original_commit_for_fix\",\"status\":\"unaffected\"}]}]}],\"metrics\":{\"cvssMetricV31\":[{\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"type\":\"Secondary\",\"cvssData\":{\"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\",\"attackVector\":\"LOCAL\",\"attackComplexity\":\"LOW\",\"privilegesRequired\":\"LOW\",\"userInteraction\":\"NONE\",\"scope\":\"UNCHANGED\",\"confidentialityImpact\":\"HIGH\",\"integrityImpact\":\"HIGH\",\"availabilityImpact\":\"HIGH\"},\"exploitabilityScore\":1.8,\"impactScore\":5.9}]},\"references\":[{\"url\":\"https://git.kernel.org/stable/c/11ad86830a78ea4e1942afc73c10e4ca8e69e03f\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/45ebe4540817cb540a59e4dc04014ac5dddc9990\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"}]}}",
    "redhat_vex": {
      "aggregate_severity": "Moderate",
      "current_release_date": "2026-08-31T08:47:56+00:00",
      "cve": "CVE-2026-80682",
      "id": "CVE-2026-80682",
      "initial_release_date": "2026-08-28T00:00:00+00:00",
      "product_status:known_not_affected": "274",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "kernel: riscv/mm: use physical alignment for vmemmap_start_pfn",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-80682.json",
      "version": "3"
    }
  }
}



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Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

Sightings

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Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
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  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.


Detection rules are retrieved from Rulezet.