CVE-2026-31600

Estado: AnalizadaAlta (7.5)—

In the Linux kernel, the following vulnerability has been resolved:

arm64: mm: Handle invalid large leaf mappings correctly

It has been possible for a long time to mark ptes in the linear map as invalid. This is done for secretmem, kfence, realm dma memory un/share, and others, by simply clearing the PTE_VALID bit. But until commit a166563e7ec37 ("arm64: mm: support large block mapping when rodata=full") large leaf mappings were never made invalid in this way.

It turns out various parts of the code base are not equipped to handle invalid large leaf mappings (in the way they are currently encoded) and I've observed a kernel panic while booting a realm guest on a BBML2_NOABORT system as a result:

Detalles técnicos trazas, registros y código del informe original

[   15.432706] software IO TLB: Memory encryption is active and system is using DMA bounce buffers
[   15.476896] Unable to handle kernel paging request at virtual address ffff000019600000
[   15.513762] Mem abort info:
[   15.527245]   ESR = 0x0000000096000046
[   15.548553]   EC = 0x25: DABT (current EL), IL = 32 bits
[   15.572146]   SET = 0, FnV = 0
[   15.592141]   EA = 0, S1PTW = 0
[   15.612694]   FSC = 0x06: level 2 translation fault
[   15.640644] Data abort info:
[   15.661983]   ISV = 0, ISS = 0x00000046, ISS2 = 0x00000000
[   15.694875]   CM = 0, WnR = 1, TnD = 0, TagAccess = 0
[   15.723740]   GCS = 0, Overlay = 0, DirtyBit = 0, Xs = 0
[   15.755776] swapper pgtable: 4k pages, 48-bit VAs, pgdp=0000000081f3f000
[   15.800410] [ffff000019600000] pgd=0000000000000000, p4d=180000009ffff403, pud=180000009fffe403, pmd=00e8000199600704
[   15.855046] Internal error: Oops: 0000000096000046 [#1]  SMP
[   15.886394] Modules linked in:
[   15.900029] CPU: 0 UID: 0 PID: 1 Comm: swapper/0 Not tainted 7.0.0-rc4-dirty #4 PREEMPT
[   15.935258] Hardware name: linux,dummy-virt (DT)
[   15.955612] pstate: 21400005 (nzCv daif +PAN -UAO -TCO +DIT -SSBS BTYPE=--)
[   15.986009] pc : __pi_memcpy_generic+0x128/0x22c
[   16.006163] lr : swiotlb_bounce+0xf4/0x158
[   16.024145] sp : ffff80008000b8f0
[   16.038896] x29: ffff80008000b8f0 x28: 0000000000000000 x27: 0000000000000000
[   16.069953] x26: ffffb3976d261ba8 x25: 0000000000000000 x24: ffff000019600000
[   16.100876] x23: 0000000000000001 x22: ffff0000043430d0 x21: 0000000000007ff0
[   16.131946] x20: 0000000084570010 x19: 0000000000000000 x18: ffff00001ffe3fcc
[   16.163073] x17: 0000000000000000 x16: 00000000003fffff x15: 646e612065766974
[   16.194131] x14: 0000000000000000 x13: 0000000000000000 x12: 0000000000000000
[   16.225059] x11: 0000000000000000 x10: 0000000000000010 x9 : 0000000000000018
[   16.256113] x8 : 0000000000000018 x7 : 0000000000000000 x6 : 0000000000000000
[   16.287203] x5 : ffff000019607ff0 x4 : ffff000004578000 x3 : ffff000019600000
[   16.318145] x2 : 0000000000007ff0 x1 : ffff000004570010 x0 : ffff000019600000
[   16.349071] Call trace:
[   16.360143]  __pi_memcpy_generic+0x128/0x22c (P)
[   16.380310]  swiotlb_tbl_map_single+0x154/0x2b4
[   16.400282]  swiotlb_map+0x5c/0x228
[   16.415984]  dma_map_phys+0x244/0x2b8
[   16.432199]  dma_map_page_attrs+0x44/0x58
[   16.449782]  virtqueue_map_page_attrs+0x38/0x44
[   16.469596]  virtqueue_map_single_attrs+0xc0/0x130
[   16.490509]  virtnet_rq_alloc.isra.0+0xa4/0x1fc
[   16.510355]  try_fill_recv+0x2a4/0x584
[   16.526989]  virtnet_open+0xd4/0x238
[   16.542775]  __dev_open+0x110/0x24c
[   16.558280]  __dev_change_flags+0x194/0x20c
[   16.576879]  netif_change_flags+0x24/0x6c
[   16.594489]  dev_change_flags+0x48/0x7c
[   16.611462]  ip_auto_config+0x258/0x1114
[   16.628727]  do_one_initcall+0x80/0x1c8
[   16.645590]  kernel_init_freeable+0x208/0x2f0
[   16.664917]  kernel_init+0x24/0x1e0
[   16.680295]  ret_from_fork+0x10/0x20
[   16.696369] Code: 927cec03 cb0e0021 8b0e0042 a9411c26 (a900340c)
[   16.723106] ---[ end trace 0000000000000000 ]---
[   16.752866] Kernel panic - not syncing: Attempted to kill init! exitcode=0x0000000b
[   16.792556] Kernel Offset: 0x3396ea200000 from 0xffff8000800000
---truncated---

CVSS

Versión: 3.1
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Puntuación base: 7.5

Probabilidad de explotación (EPSS)

Probabilidad de explotación en los próximos 30 días: 0.40%
Percentil entre todas las CVEs puntuadas: 32
Fecha de la puntuación: 5/10/2026

EPSS (Exploit Prediction Scoring System, de FIRST) estima la probabilidad de que una vulnerabilidad sea explotada en 30 días. Complementa a CVSS (impacto) y a CISA KEV (explotación confirmada).

🎯 Técnicas ATT&CK

Cómo se explota esta vulnerabilidad y qué consigue el atacante, en el lenguaje de MITRE ATT&CK.

ExplotaciónT1190 Exploit Public-Facing Applicationinitial access60 %
Impacto principalT1499 Endpoint Denial of Serviceimpact55 %

Inferido por reglas deterministas a partir del vector CVSS y la CWE. Solo orientativo.

🛡️ Mitigaciones ATT&CK que cubren estas técnicas

Filter Network Traffic Vulnerability Scanning Privileged Account Management Network Segmentation Limit Access to Resource Over Network Application Isolation and Sandboxing

Tecnologías afectadas (1)

Linux — Linux Kernel

CWE

CWE-476

Referencias

JSON original (NVD)

Mostrar

{
  "id": "CVE-2026-31600",
  "cveTags": [],
  "metrics": {
    "cvssMetricV31": [
      {
        "type": "Secondary",
        "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "cvssData": {
          "scope": "UNCHANGED",
          "version": "3.1",
          "baseScore": 7.5,
          "attackVector": "NETWORK",
          "baseSeverity": "HIGH",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
          "integrityImpact": "NONE",
          "userInteraction": "NONE",
          "attackComplexity": "LOW",
          "availabilityImpact": "HIGH",
          "privilegesRequired": "NONE",
          "confidentialityImpact": "NONE"
        },
        "impactScore": 3.6,
        "exploitabilityScore": 3.9
      }
    ]
  },
  "affected": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "affectedData": [
        {
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "product": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "a166563e7ec375b38a0fd3a58f7b77e50a6bc6a8",
              "lessThan": "8140b21d19015227a28c255404462f2d3e6edc9a",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "a166563e7ec375b38a0fd3a58f7b77e50a6bc6a8",
              "lessThan": "747b6482e4e227fd351197dde6f64a97107a9e52",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "a166563e7ec375b38a0fd3a58f7b77e50a6bc6a8",
              "lessThan": "cbea627ea634f41c79d18f0c6d20db66fa93514c",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "a166563e7ec375b38a0fd3a58f7b77e50a6bc6a8",
              "lessThan": "15bfba1ad77fad8e45a37aae54b3c813b33fe27c",
              "versionType": "git"
            }
          ],
          "programFiles": [
            "arch/arm64/include/asm/pgtable-prot.h",
            "arch/arm64/include/asm/pgtable.h",
            "arch/arm64/mm/mmu.c",
            "arch/arm64/mm/pageattr.c",
            "arch/arm64/mm/trans_pgd.c"
          ],
          "defaultStatus": "unaffected"
        },
        {
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "product": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "6.18"
            },
            {
              "status": "unaffected",
              "version": "0",
              "lessThan": "6.18",
              "versionType": "semver"
            },
            {
              "status": "unaffected",
              "version": "6.18.24",
              "versionType": "semver",
              "lessThanOrEqual": "6.18.*"
            },
            {
              "status": "unaffected",
              "version": "6.19.14",
              "versionType": "semver",
              "lessThanOrEqual": "6.19.*"
            },
            {
              "status": "unaffected",
              "version": "7.0.1",
              "versionType": "semver",
              "lessThanOrEqual": "7.0.*"
            },
            {
              "status": "unaffected",
              "version": "7.1",
              "versionType": "original_commit_for_fix",
              "lessThanOrEqual": "*"
            }
          ],
          "programFiles": [
            "arch/arm64/include/asm/pgtable-prot.h",
            "arch/arm64/include/asm/pgtable.h",
            "arch/arm64/mm/mmu.c",
            "arch/arm64/mm/pageattr.c",
            "arch/arm64/mm/trans_pgd.c"
          ],
          "defaultStatus": "affected"
        }
      ]
    }
  ],
  "published": "2026-04-24T15:16:38.920",
  "references": [
    {
      "url": "https://git.kernel.org/stable/c/15bfba1ad77fad8e45a37aae54b3c813b33fe27c",
      "tags": [
        "Patch"
      ],
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/747b6482e4e227fd351197dde6f64a97107a9e52",
      "tags": [
        "Patch"
      ],
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/8140b21d19015227a28c255404462f2d3e6edc9a",
      "tags": [
        "Patch"
      ],
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/cbea627ea634f41c79d18f0c6d20db66fa93514c",
      "tags": [
        "Patch"
      ],
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "vulnStatus": "Analyzed",
  "weaknesses": [
    {
      "type": "Primary",
      "source": "nvd@nist.gov",
      "description": [
        {
          "lang": "en",
          "value": "CWE-476"
        }
      ]
    }
  ],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\narm64: mm: Handle invalid large leaf mappings correctly\n\nIt has been possible for a long time to mark ptes in the linear map as\ninvalid. This is done for secretmem, kfence, realm dma memory un/share,\nand others, by simply clearing the PTE_VALID bit. But until commit\na166563e7ec37 (\"arm64: mm: support large block mapping when\nrodata=full\") large leaf mappings were never made invalid in this way.\n\nIt turns out various parts of the code base are not equipped to handle\ninvalid large leaf mappings (in the way they are currently encoded) and\nI've observed a kernel panic while booting a realm guest on a\nBBML2_NOABORT system as a result:\n\n[   15.432706] software IO TLB: Memory encryption is active and system is using DMA bounce buffers\n[   15.476896] Unable to handle kernel paging request at virtual address ffff000019600000\n[   15.513762] Mem abort info:\n[   15.527245]   ESR = 0x0000000096000046\n[   15.548553]   EC = 0x25: DABT (current EL), IL = 32 bits\n[   15.572146]   SET = 0, FnV = 0\n[   15.592141]   EA = 0, S1PTW = 0\n[   15.612694]   FSC = 0x06: level 2 translation fault\n[   15.640644] Data abort info:\n[   15.661983]   ISV = 0, ISS = 0x00000046, ISS2 = 0x00000000\n[   15.694875]   CM = 0, WnR = 1, TnD = 0, TagAccess = 0\n[   15.723740]   GCS = 0, Overlay = 0, DirtyBit = 0, Xs = 0\n[   15.755776] swapper pgtable: 4k pages, 48-bit VAs, pgdp=0000000081f3f000\n[   15.800410] [ffff000019600000] pgd=0000000000000000, p4d=180000009ffff403, pud=180000009fffe403, pmd=00e8000199600704\n[   15.855046] Internal error: Oops: 0000000096000046 [#1]  SMP\n[   15.886394] Modules linked in:\n[   15.900029] CPU: 0 UID: 0 PID: 1 Comm: swapper/0 Not tainted 7.0.0-rc4-dirty #4 PREEMPT\n[   15.935258] Hardware name: linux,dummy-virt (DT)\n[   15.955612] pstate: 21400005 (nzCv daif +PAN -UAO -TCO +DIT -SSBS BTYPE=--)\n[   15.986009] pc : __pi_memcpy_generic+0x128/0x22c\n[   16.006163] lr : swiotlb_bounce+0xf4/0x158\n[   16.024145] sp : ffff80008000b8f0\n[   16.038896] x29: ffff80008000b8f0 x28: 0000000000000000 x27: 0000000000000000\n[   16.069953] x26: ffffb3976d261ba8 x25: 0000000000000000 x24: ffff000019600000\n[   16.100876] x23: 0000000000000001 x22: ffff0000043430d0 x21: 0000000000007ff0\n[   16.131946] x20: 0000000084570010 x19: 0000000000000000 x18: ffff00001ffe3fcc\n[   16.163073] x17: 0000000000000000 x16: 00000000003fffff x15: 646e612065766974\n[   16.194131] x14: 0000000000000000 x13: 0000000000000000 x12: 0000000000000000\n[   16.225059] x11: 0000000000000000 x10: 0000000000000010 x9 : 0000000000000018\n[   16.256113] x8 : 0000000000000018 x7 : 0000000000000000 x6 : 0000000000000000\n[   16.287203] x5 : ffff000019607ff0 x4 : ffff000004578000 x3 : ffff000019600000\n[   16.318145] x2 : 0000000000007ff0 x1 : ffff000004570010 x0 : ffff000019600000\n[   16.349071] Call trace:\n[   16.360143]  __pi_memcpy_generic+0x128/0x22c (P)\n[   16.380310]  swiotlb_tbl_map_single+0x154/0x2b4\n[   16.400282]  swiotlb_map+0x5c/0x228\n[   16.415984]  dma_map_phys+0x244/0x2b8\n[   16.432199]  dma_map_page_attrs+0x44/0x58\n[   16.449782]  virtqueue_map_page_attrs+0x38/0x44\n[   16.469596]  virtqueue_map_single_attrs+0xc0/0x130\n[   16.490509]  virtnet_rq_alloc.isra.0+0xa4/0x1fc\n[   16.510355]  try_fill_recv+0x2a4/0x584\n[   16.526989]  virtnet_open+0xd4/0x238\n[   16.542775]  __dev_open+0x110/0x24c\n[   16.558280]  __dev_change_flags+0x194/0x20c\n[   16.576879]  netif_change_flags+0x24/0x6c\n[   16.594489]  dev_change_flags+0x48/0x7c\n[   16.611462]  ip_auto_config+0x258/0x1114\n[   16.628727]  do_one_initcall+0x80/0x1c8\n[   16.645590]  kernel_init_freeable+0x208/0x2f0\n[   16.664917]  kernel_init+0x24/0x1e0\n[   16.680295]  ret_from_fork+0x10/0x20\n[   16.696369] Code: 927cec03 cb0e0021 8b0e0042 a9411c26 (a900340c)\n[   16.723106] ---[ end trace 0000000000000000 ]---\n[   16.752866] Kernel panic - not syncing: Attempted to kill init! exitcode=0x0000000b\n[   16.792556] Kernel Offset: 0x3396ea200000 from 0xffff8000800000\n---truncated---"
    }
  ],
  "lastModified": "2026-06-17T10:34:03.813",
  "configurations": [
    {
      "nodes": [
        {
          "negate": false,
          "cpeMatch": [
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
              "vulnerable": true,
              "matchCriteriaId": "4C4EAA6A-7949-4B29-BD69-5BB05C4D1A6B",
              "versionEndExcluding": "6.18.24",
              "versionStartIncluding": "6.18"
            },
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
              "vulnerable": true,
              "matchCriteriaId": "D6A8A074-BBF4-4803-ABED-519A839435BB",
              "versionEndExcluding": "6.19.14",
              "versionStartIncluding": "6.19"
            },
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
              "vulnerable": true,
              "matchCriteriaId": "9B5888AB-7403-4335-89E4-21CC0B48366A",
              "versionEndExcluding": "7.0.1",
              "versionStartIncluding": "7.0"
            }
          ],
          "operator": "OR"
        }
      ]
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}