CVE-2025-40006

Estado: AplazadaAlta (7.8)—

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

mm/hugetlb: fix folio is still mapped when deleted

Migration may be raced with fallocating hole. remove_inode_single_folio will unmap the folio if the folio is still mapped. However, it's called without folio lock. If the folio is migrated and the mapped pte has been converted to migration entry, folio_mapped() returns false, and won't unmap it. Due to extra refcount held by remove_inode_single_folio, migration fails, restores migration entry to normal pte, and the folio is mapped again. As a result, we triggered BUG in filemap_unaccount_folio.

Leer descripción completaMostrar menos

Hold folio lock before checking if the folio is mapped to avold race with migration.

Detalles técnicos trazas, registros y código del informe original

The log is as follows:
 BUG: Bad page cache in process hugetlb  pfn:156c00
 page: refcount:515 mapcount:0 mapping:0000000099fef6e1 index:0x0 pfn:0x156c00
 head: order:9 mapcount:1 entire_mapcount:1 nr_pages_mapped:0 pincount:0
 aops:hugetlbfs_aops ino:dcc dentry name(?):"my_hugepage_file"
 flags: 0x17ffffc00000c1(locked|waiters|head|node=0|zone=2|lastcpupid=0x1fffff)
 page_type: f4(hugetlb)
 page dumped because: still mapped when deleted
 CPU: 1 UID: 0 PID: 395 Comm: hugetlb Not tainted 6.17.0-rc5-00044-g7aac71907bde-dirty #484 NONE
 Hardware name: QEMU Ubuntu 24.04 PC (i440FX + PIIX, 1996), BIOS 0.0.0 02/06/2015
 Call Trace:
  <TASK>
  dump_stack_lvl+0x4f/0x70
  filemap_unaccount_folio+0xc4/0x1c0
  __filemap_remove_folio+0x38/0x1c0
  filemap_remove_folio+0x41/0xd0
  remove_inode_hugepages+0x142/0x250
  hugetlbfs_fallocate+0x471/0x5a0
  vfs_fallocate+0x149/0x380

CVSS

Versión: 3.1
Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Puntuación base: 7.8

Probabilidad de explotación (EPSS)

Probabilidad de explotación en los próximos 30 días: 0.20%
Percentil entre todas las CVEs puntuadas: 9
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).

🎯 Técnicas ATT&CK

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

ExplotaciónT1068 Exploitation for Privilege Escalationprivilege escalation75 %
Impacto principalT1499.004 Application or System Exploitationimpact65 %

Vulnerabilidad de escalada local (AV:L, PR:L, UI:N) en kernel Linux que causa condición de carrera; explotación requiere acceso local ya establecido. El impacto es DoS por corrupción de memoria (BUG in filemap_unaccount_folio).

Inferido por nuestro agente de análisis a partir de la descripción oficial, el vector CVSS y la CWE, y comprobado por un supervisor. Puede contener errores.

🛡️ Mitigaciones ATT&CK que cubren estas técnicas

Threat Intelligence Program Filter Network Traffic Execution Prevention Application Isolation and Sandboxing Exploit Protection Update Software

Tecnologías afectadas (1)

⚠ Inferidas por IA a partir de la descripción — NVD aún no ha analizado esta CVE; no son CPE verificados.

Linux — Linux Kernel^AI

Referencias

JSON original (NVD)

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{
  "id": "CVE-2025-40006",
  "cveTags": [],
  "metrics": {
    "cvssMetricV31": [
      {
        "type": "Secondary",
        "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "cvssData": {
          "scope": "UNCHANGED",
          "version": "3.1",
          "baseScore": 7.8,
          "attackVector": "LOCAL",
          "baseSeverity": "HIGH",
          "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
          "integrityImpact": "HIGH",
          "userInteraction": "NONE",
          "attackComplexity": "LOW",
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          "privilegesRequired": "LOW",
          "confidentialityImpact": "HIGH"
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  "published": "2025-10-20T16:15:37.240",
  "references": [
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      "url": "https://git.kernel.org/stable/c/21ee79ce938127f88fe07e409c1817f477dbe7ea",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
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      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "vulnStatus": "Deferred",
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nmm/hugetlb: fix folio is still mapped when deleted\n\nMigration may be raced with fallocating hole.  remove_inode_single_folio\nwill unmap the folio if the folio is still mapped.  However, it's called\nwithout folio lock.  If the folio is migrated and the mapped pte has been\nconverted to migration entry, folio_mapped() returns false, and won't\nunmap it.  Due to extra refcount held by remove_inode_single_folio,\nmigration fails, restores migration entry to normal pte, and the folio is\nmapped again.  As a result, we triggered BUG in filemap_unaccount_folio.\n\nThe log is as follows:\n BUG: Bad page cache in process hugetlb  pfn:156c00\n page: refcount:515 mapcount:0 mapping:0000000099fef6e1 index:0x0 pfn:0x156c00\n head: order:9 mapcount:1 entire_mapcount:1 nr_pages_mapped:0 pincount:0\n aops:hugetlbfs_aops ino:dcc dentry name(?):\"my_hugepage_file\"\n flags: 0x17ffffc00000c1(locked|waiters|head|node=0|zone=2|lastcpupid=0x1fffff)\n page_type: f4(hugetlb)\n page dumped because: still mapped when deleted\n CPU: 1 UID: 0 PID: 395 Comm: hugetlb Not tainted 6.17.0-rc5-00044-g7aac71907bde-dirty #484 NONE\n Hardware name: QEMU Ubuntu 24.04 PC (i440FX + PIIX, 1996), BIOS 0.0.0 02/06/2015\n Call Trace:\n  <TASK>\n  dump_stack_lvl+0x4f/0x70\n  filemap_unaccount_folio+0xc4/0x1c0\n  __filemap_remove_folio+0x38/0x1c0\n  filemap_remove_folio+0x41/0xd0\n  remove_inode_hugepages+0x142/0x250\n  hugetlbfs_fallocate+0x471/0x5a0\n  vfs_fallocate+0x149/0x380\n\nHold folio lock before checking if the folio is mapped to avold race with\nmigration."
    }
  ],
  "lastModified": "2026-07-30T06:24:05.993",
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}