CVE-2025-38050

Estado: AnalizadaMedia (5.5)—

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

mm/hugetlb: fix kernel NULL pointer dereference when replacing free hugetlb folios

A kernel crash was observed when replacing free hugetlb folios:

There is a potential race between __update_and_free_hugetlb_folio() and replace_free_hugepage_folios():

When the above race condition occurs, folio_hstate(folio) returns NULL, and subsequent access to this NULL pointer will cause the system to crash. To resolve this issue, execute folio_hstate(folio) under the protection of the hugetlb_lock lock, ensuring that folio_hstate(folio) does not return NULL.

Detalles técnicos trazas, registros y código del informe original

BUG: kernel NULL pointer dereference, address: 0000000000000028
PGD 0 P4D 0
Oops: Oops: 0000 [#1] SMP NOPTI
CPU: 28 UID: 0 PID: 29639 Comm: test_cma.sh Tainted 6.15.0-rc6-zp #41 PREEMPT(voluntary)
RIP: 0010:alloc_and_dissolve_hugetlb_folio+0x1d/0x1f0
RSP: 0018:ffffc9000b30fa90 EFLAGS: 00010286
RAX: 0000000000000000 RBX: 0000000000342cca RCX: ffffea0043000000
RDX: ffffc9000b30fb08 RSI: ffffea0043000000 RDI: 0000000000000000
RBP: ffffc9000b30fb20 R08: 0000000000001000 R09: 0000000000000000
R10: ffff88886f92eb00 R11: 0000000000000000 R12: ffffea0043000000
R13: 0000000000000000 R14: 00000000010c0200 R15: 0000000000000004
FS:  00007fcda5f14740(0000) GS:ffff8888ec1d8000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000028 CR3: 0000000391402000 CR4: 0000000000350ef0
Call Trace:
<TASK>
 replace_free_hugepage_folios+0xb6/0x100
 alloc_contig_range_noprof+0x18a/0x590
 ? srso_return_thunk+0x5/0x5f
 ? down_read+0x12/0xa0
 ? srso_return_thunk+0x5/0x5f
 cma_range_alloc.constprop.0+0x131/0x290
 __cma_alloc+0xcf/0x2c0
 cma_alloc_write+0x43/0xb0
 simple_attr_write_xsigned.constprop.0.isra.0+0xb2/0x110
 debugfs_attr_write+0x46/0x70
 full_proxy_write+0x62/0xa0
 vfs_write+0xf8/0x420
 ? srso_return_thunk+0x5/0x5f
 ? filp_flush+0x86/0xa0
 ? srso_return_thunk+0x5/0x5f
 ? filp_close+0x1f/0x30
 ? srso_return_thunk+0x5/0x5f
 ? do_dup2+0xaf/0x160
 ? srso_return_thunk+0x5/0x5f
 ksys_write+0x65/0xe0
 do_syscall_64+0x64/0x170
 entry_SYSCALL_64_after_hwframe+0x76/0x7e

CPU1                              CPU2
__update_and_free_hugetlb_folio   replace_free_hugepage_folios
                                    folio_test_hugetlb(folio)
                                    -- It's still hugetlb folio.

  __folio_clear_hugetlb(folio)
  hugetlb_free_folio(folio)
                                    h = folio_hstate(folio)
                                    -- Here, h is NULL pointer

CVSS

Versión: 3.1
Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Puntuación base: 5.5

Probabilidad de explotación (EPSS)

Probabilidad de explotación en los próximos 30 días: 0.16%
Percentil entre todas las CVEs puntuadas: 4
Fecha de la puntuación: 6/10/2026

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).

Tecnologías afectadas (1)

Linux — Linux Kernel

CWE

CWE-476

Referencias

JSON original (NVD)

Mostrar

{
  "id": "CVE-2025-38050",
  "cveTags": [],
  "metrics": {
    "cvssMetricV31": [
      {
        "type": "Primary",
        "source": "nvd@nist.gov",
        "cvssData": {
          "scope": "UNCHANGED",
          "version": "3.1",
          "baseScore": 5.5,
          "attackVector": "LOCAL",
          "baseSeverity": "MEDIUM",
          "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H",
          "integrityImpact": "NONE",
          "userInteraction": "NONE",
          "attackComplexity": "LOW",
          "availabilityImpact": "HIGH",
          "privilegesRequired": "LOW",
          "confidentialityImpact": "NONE"
        },
        "impactScore": 3.6,
        "exploitabilityScore": 1.8
      }
    ]
  },
  "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": "04f13d241b8b146b23038bffd907cb8278391d07",
              "lessThan": "e97283978a9848190d451f7038ac399613445f79",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "04f13d241b8b146b23038bffd907cb8278391d07",
              "lessThan": "113ed54ad276c352ee5ce109bdcf0df118a43bda",
              "versionType": "git"
            }
          ],
          "programFiles": [
            "mm/hugetlb.c"
          ],
          "defaultStatus": "unaffected"
        },
        {
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "product": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "6.14"
            },
            {
              "status": "unaffected",
              "version": "0",
              "lessThan": "6.14",
              "versionType": "semver"
            },
            {
              "status": "unaffected",
              "version": "6.14.9",
              "versionType": "semver",
              "lessThanOrEqual": "6.14.*"
            },
            {
              "status": "unaffected",
              "version": "6.15",
              "versionType": "original_commit_for_fix",
              "lessThanOrEqual": "*"
            }
          ],
          "programFiles": [
            "mm/hugetlb.c"
          ],
          "defaultStatus": "affected"
        }
      ]
    }
  ],
  "published": "2025-06-18T10:15:37.570",
  "references": [
    {
      "url": "https://git.kernel.org/stable/c/113ed54ad276c352ee5ce109bdcf0df118a43bda",
      "tags": [
        "Patch"
      ],
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/e97283978a9848190d451f7038ac399613445f79",
      "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\nmm/hugetlb: fix kernel NULL pointer dereference when replacing free hugetlb folios\n\nA kernel crash was observed when replacing free hugetlb folios:\n\nBUG: kernel NULL pointer dereference, address: 0000000000000028\nPGD 0 P4D 0\nOops: Oops: 0000 [#1] SMP NOPTI\nCPU: 28 UID: 0 PID: 29639 Comm: test_cma.sh Tainted 6.15.0-rc6-zp #41 PREEMPT(voluntary)\nRIP: 0010:alloc_and_dissolve_hugetlb_folio+0x1d/0x1f0\nRSP: 0018:ffffc9000b30fa90 EFLAGS: 00010286\nRAX: 0000000000000000 RBX: 0000000000342cca RCX: ffffea0043000000\nRDX: ffffc9000b30fb08 RSI: ffffea0043000000 RDI: 0000000000000000\nRBP: ffffc9000b30fb20 R08: 0000000000001000 R09: 0000000000000000\nR10: ffff88886f92eb00 R11: 0000000000000000 R12: ffffea0043000000\nR13: 0000000000000000 R14: 00000000010c0200 R15: 0000000000000004\nFS:  00007fcda5f14740(0000) GS:ffff8888ec1d8000(0000) knlGS:0000000000000000\nCS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033\nCR2: 0000000000000028 CR3: 0000000391402000 CR4: 0000000000350ef0\nCall Trace:\n<TASK>\n replace_free_hugepage_folios+0xb6/0x100\n alloc_contig_range_noprof+0x18a/0x590\n ? srso_return_thunk+0x5/0x5f\n ? down_read+0x12/0xa0\n ? srso_return_thunk+0x5/0x5f\n cma_range_alloc.constprop.0+0x131/0x290\n __cma_alloc+0xcf/0x2c0\n cma_alloc_write+0x43/0xb0\n simple_attr_write_xsigned.constprop.0.isra.0+0xb2/0x110\n debugfs_attr_write+0x46/0x70\n full_proxy_write+0x62/0xa0\n vfs_write+0xf8/0x420\n ? srso_return_thunk+0x5/0x5f\n ? filp_flush+0x86/0xa0\n ? srso_return_thunk+0x5/0x5f\n ? filp_close+0x1f/0x30\n ? srso_return_thunk+0x5/0x5f\n ? do_dup2+0xaf/0x160\n ? srso_return_thunk+0x5/0x5f\n ksys_write+0x65/0xe0\n do_syscall_64+0x64/0x170\n entry_SYSCALL_64_after_hwframe+0x76/0x7e\n\nThere is a potential race between __update_and_free_hugetlb_folio() and\nreplace_free_hugepage_folios():\n\nCPU1                              CPU2\n__update_and_free_hugetlb_folio   replace_free_hugepage_folios\n                                    folio_test_hugetlb(folio)\n                                    -- It's still hugetlb folio.\n\n  __folio_clear_hugetlb(folio)\n  hugetlb_free_folio(folio)\n                                    h = folio_hstate(folio)\n                                    -- Here, h is NULL pointer\n\nWhen the above race condition occurs, folio_hstate(folio) returns NULL,\nand subsequent access to this NULL pointer will cause the system to crash.\nTo resolve this issue, execute folio_hstate(folio) under the protection\nof the hugetlb_lock lock, ensuring that folio_hstate(folio) does not\nreturn NULL."
    },
    {
      "lang": "es",
      "value": "En el kernel de Linux, se ha resuelto la siguiente vulnerabilidad: mm/hugetlb: corrección de la desreferencia del puntero NULL del kernel al reemplazar folios hugetlb libres Se observó un fallo del kernel al reemplazar folios hugetlb libres: ERROR: desreferencia del puntero NULL del kernel, dirección: 0000000000000028 PGD 0 P4D 0 Oops: Oops: 0000 [#1] SMP NOPTI CPU: 28 UID: 0 PID: 29639 Comm: test_cma.sh Tainted 6.15.0-rc6-zp #41 PREEMPT(voluntario) RIP: 0010:alloc_and_dissolve_hugetlb_folio+0x1d/0x1f0 RSP: 0018:ffffc9000b30fa90 EFLAGS: 00010286 RAX: 0000000000000000 RBX: 0000000000342cca RCX: ffffea0043000000 RDX: ffffc9000b30fb08 RSI: ffffea0043000000 RDI: 0000000000000000 RBP: ffffc9000b30fb20 R08: 0000000000001000 R09: 0000000000000000 R10: ffff88886f92eb00 R11: 000000000000000000 R12: ffffea0043000000 R13: 0000000000000000 R14: 00000000010c0200 R15: 0000000000000004 FS: 00007fcda5f14740(0000) GS:ffff8888ec1d8000(0000) knlGS:000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000000000000028 CR3: 0000000391402000 CR4: 0000000000350ef0 Rastreo de llamadas:  replace_free_hugepage_folios+0xb6/0x100 alloc_contig_range_noprof+0x18a/0x590 ? srso_return_thunk+0x5/0x5f ? down_read+0x12/0xa0 ? srso_return_thunk+0x5/0x5f cma_range_alloc.constprop.0+0x131/0x290 __cma_alloc+0xcf/0x2c0 cma_alloc_write+0x43/0xb0 simple_attr_write_xsigned.constprop.0.isra.0+0xb2/0x110 debugfs_attr_write+0x46/0x70 full_proxy_write+0x62/0xa0 vfs_write+0xf8/0x420 ? srso_return_thunk+0x5/0x5f ? filp_flush+0x86/0xa0 ? srso_return_thunk+0x5/0x5f ? filp_close+0x1f/0x30 ? srso_return_thunk+0x5/0x5f ? do_dup2+0xaf/0x160 ? srso_return_thunk+0x5/0x5f ksys_write+0x65/0xe0 do_syscall_64+0x64/0x170 entry_SYSCALL_64_after_hwframe+0x76/0x7e There is a potential race between __update_and_free_hugetlb_folio() and replace_free_hugepage_folios(): CPU1 CPU2 __update_and_free_hugetlb_folio replace_free_hugepage_folios folio_test_hugetlb(folio) -- It's still hugetlb folio. __folio_clear_hugetlb(folio) hugetlb_free_folio(folio) h = folio_hstate(folio) -- Aquí, h es un puntero NULL Cuando ocurre la condición de ejecución anterior, folio_hstate(folio) devuelve NULL y el acceso posterior a este puntero NULL provocará que el sistema se bloquee. Para resolver este problema, ejecute folio_hstate(folio) bajo la protección del bloqueo hugetlb_lock, asegurándose de que folio_hstate(folio) no devuelva NULL."
    }
  ],
  "lastModified": "2026-06-17T09:15:57.213",
  "configurations": [
    {
      "nodes": [
        {
          "negate": false,
          "cpeMatch": [
            {
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              "versionEndExcluding": "6.14.9",
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}