CVE-2026-64108

Estado: AnalizadaAlta (7.8)—

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

cifs: Fix busy dentry used after unmounting

Since commit 340cea84f691c ("cifs: open files should not hold ref on superblock"), cifs file only holds the dentry ref_cnt, the cifs file close work(cfile->deferred) could be executed after unmounting, which will trigger a warning in generic_shutdown_super: BUG: Dentry 00000000a14a6845{i=c,n=file} still in use (1) [unmount of cifs cifs]

The detailed processs is: process A process B kworker fd = open(PATH) vfs_open file->__f_path = *path // dentry->d_lockref.count = 1 cifs_open cifs_new_fileinfo cfile->dentry = dget(dentry) // dentry->d_lockref.count = 2 close(fd) __fput cifs_close queue_delayed_work(deferredclose_wq, cfile->deferred) dput(dentry) // dentry->d_lockref.count = 1 smb2_deferred_work_close _cifsFileInfo_put list_del(&cifs_file->flist) umount cleanup_mnt deactivate_super cifs_kill_sb cifs_close_all_deferred_files_sb cifs_close_all_deferred_files // cannot find cfile, skip _cifsFileInfo_put kill_anon_super generic_shutdown_super shrink_dcache_for_umount umount_check WARN ! // dentry->d_lockref.count = 1 cifsFileInfo_put_final dput(cifs_file->dentry) // dentry->d_lockref.count = 0

Leer descripción completaMostrar menos

Fix it by flushing 'deferredclose_wq' before calling kill_anon_super.

Fetch a reproducer in https://bugzilla.kernel.org/show_bug.cgi?id=221548.

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: 0.18%
Percentil entre todas las CVEs puntuadas: 6
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.

ExplotaciónT1068 Exploitation for Privilege Escalationprivilege escalation75 %
Impacto principalT1499.004 Application or System Exploitationimpact70 %

Vulnerabilidad de escalada local en kernel Linux (AV:L, PR:L) que causa condición de carrera en dentry/dput, resultando en DoS por exhaustión de recursos (uso después de liberación de memoria).

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)

Linux — Linux Kernel

CWE

NVD-CWE-noinfo

Referencias

JSON original (NVD)

Mostrar

{
  "id": "CVE-2026-64108",
  "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",
          "availabilityImpact": "HIGH",
          "privilegesRequired": "LOW",
          "confidentialityImpact": "HIGH"
        },
        "impactScore": 5.9,
        "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": "708c276f516d27beaded7f372ac8111cee43926c",
              "lessThan": "c7364cea52531534676b9f7dbc0a477c11f4c050",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "0629a1a187e424373364d681b42b101894bdb548",
              "lessThan": "bdc349a87f1fb02c18c4071858a06542bfea783d",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "0e4b8faaaebe3137bec5723ef2b3cb0437fb38fd",
              "lessThan": "f2deaa2f409a4598eaa10f2a93a676c0632af248",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "f655467a9973f964b267871e5fef533ad5014494",
              "lessThan": "5e7d9d0805e58fa3760894e73115b7a74024fd07",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "340cea84f691c5206561bb2e0147158fe02070be",
              "lessThan": "e1ffa6cf662383f95816eed1b623429d82675e75",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "340cea84f691c5206561bb2e0147158fe02070be",
              "lessThan": "c68337442f03953237a94577beb468ab2662a851",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "30afc6ea72cc6cf7c8d579e79b64232801c38d08",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "6.1.167",
              "lessThan": "6.1.175",
              "versionType": "semver"
            },
            {
              "status": "affected",
              "version": "6.6.130",
              "lessThan": "6.6.142",
              "versionType": "semver"
            },
            {
              "status": "affected",
              "version": "6.12.78",
              "lessThan": "6.12.92",
              "versionType": "semver"
            },
            {
              "status": "affected",
              "version": "6.18.20",
              "lessThan": "6.18.34",
              "versionType": "semver"
            },
            {
              "status": "affected",
              "version": "6.19.10",
              "lessThan": "6.20",
              "versionType": "semver"
            }
          ],
          "programFiles": [
            "fs/smb/client/cifsfs.c"
          ],
          "defaultStatus": "unaffected"
        },
        {
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "product": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "7.0"
            },
            {
              "status": "unaffected",
              "version": "0",
              "lessThan": "7.0",
              "versionType": "semver"
            },
            {
              "status": "unaffected",
              "version": "6.1.175",
              "versionType": "semver",
              "lessThanOrEqual": "6.1.*"
            },
            {
              "status": "unaffected",
              "version": "6.6.142",
              "versionType": "semver",
              "lessThanOrEqual": "6.6.*"
            },
            {
              "status": "unaffected",
              "version": "6.12.92",
              "versionType": "semver",
              "lessThanOrEqual": "6.12.*"
            },
            {
              "status": "unaffected",
              "version": "6.18.34",
              "versionType": "semver",
              "lessThanOrEqual": "6.18.*"
            },
            {
              "status": "unaffected",
              "version": "7.0.11",
              "versionType": "semver",
              "lessThanOrEqual": "7.0.*"
            },
            {
              "status": "unaffected",
              "version": "7.1",
              "versionType": "original_commit_for_fix",
              "lessThanOrEqual": "*"
            }
          ],
          "programFiles": [
            "fs/smb/client/cifsfs.c"
          ],
          "defaultStatus": "affected"
        }
      ]
    }
  ],
  "published": "2026-07-19T16:17:52.100",
  "references": [
    {
      "url": "https://git.kernel.org/stable/c/5e7d9d0805e58fa3760894e73115b7a74024fd07",
      "tags": [
        "Patch"
      ],
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/bdc349a87f1fb02c18c4071858a06542bfea783d",
      "tags": [
        "Patch"
      ],
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/c68337442f03953237a94577beb468ab2662a851",
      "tags": [
        "Patch"
      ],
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/c7364cea52531534676b9f7dbc0a477c11f4c050",
      "tags": [
        "Patch"
      ],
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/e1ffa6cf662383f95816eed1b623429d82675e75",
      "tags": [
        "Patch"
      ],
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/f2deaa2f409a4598eaa10f2a93a676c0632af248",
      "tags": [
        "Patch"
      ],
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "vulnStatus": "Analyzed",
  "weaknesses": [
    {
      "type": "Primary",
      "source": "nvd@nist.gov",
      "description": [
        {
          "lang": "en",
          "value": "NVD-CWE-noinfo"
        }
      ]
    }
  ],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\ncifs: Fix busy dentry used after unmounting\n\nSince commit 340cea84f691c (\"cifs: open files should not hold ref on\nsuperblock\"), cifs file only holds the dentry ref_cnt, the cifs file\nclose work(cfile->deferred) could be executed after unmounting, which\nwill trigger a warning in generic_shutdown_super:\n BUG: Dentry 00000000a14a6845{i=c,n=file}  still in use (1) [unmount of\n cifs cifs]\n\nThe detailed processs is:\n   process A           process B           kworker\n fd = open(PATH)\n  vfs_open\n   file->__f_path = *path // dentry->d_lockref.count = 1\n   cifs_open\n    cifs_new_fileinfo\n     cfile->dentry = dget(dentry) // dentry->d_lockref.count = 2\n close(fd)\n  __fput\n  cifs_close\n   queue_delayed_work(deferredclose_wq, cfile->deferred)\n  dput(dentry) // dentry->d_lockref.count = 1\n\t\t\t                 smb2_deferred_work_close\n\t\t\t\t\t  _cifsFileInfo_put\n\t\t\t\t\t   list_del(&cifs_file->flist)\n                    umount\n\t\t     cleanup_mnt\n\t\t      deactivate_super\n\t\t       cifs_kill_sb\n\t\t        cifs_close_all_deferred_files_sb\n\t\t\t cifs_close_all_deferred_files\n\t\t\t  // cannot find cfile, skip _cifsFileInfo_put\n\t\t\tkill_anon_super\n\t\t\t generic_shutdown_super\n\t\t\t  shrink_dcache_for_umount\n\t\t\t   umount_check\n\t\t\t    WARN ! // dentry->d_lockref.count = 1\n\t\t\t\t\t   cifsFileInfo_put_final\n\t\t\t\t\t    dput(cifs_file->dentry)\n\t\t                            // dentry->d_lockref.count = 0\n\nFix it by flushing 'deferredclose_wq' before calling kill_anon_super.\n\nFetch a reproducer in https://bugzilla.kernel.org/show_bug.cgi?id=221548."
    }
  ],
  "lastModified": "2026-08-12T15:14:14.520",
  "configurations": [
    {
      "nodes": [
        {
          "negate": false,
          "cpeMatch": [
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
              "vulnerable": true,
              "matchCriteriaId": "CDF8E8A0-BCFF-48A3-99D3-DCB981103267",
              "versionEndExcluding": "6.1.175",
              "versionStartIncluding": "6.1.167"
            },
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
              "vulnerable": true,
              "matchCriteriaId": "058207F9-2E6B-49A4-AB8C-A75B7972DA9D",
              "versionEndExcluding": "6.6.142",
              "versionStartIncluding": "6.6.130"
            },
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
              "vulnerable": true,
              "matchCriteriaId": "13356F83-00D9-403C-B3A0-65983F234D6F",
              "versionEndExcluding": "6.12.92",
              "versionStartIncluding": "6.12.78"
            },
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
              "vulnerable": true,
              "matchCriteriaId": "EC619BC6-058F-4EDF-B518-B64F6A5DD2E8",
              "versionEndExcluding": "6.18.34",
              "versionStartIncluding": "6.18.20"
            },
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
              "vulnerable": true,
              "matchCriteriaId": "5660E677-FDE2-49F2-9713-4B143B1CEDCC",
              "versionEndExcluding": "7.0",
              "versionStartIncluding": "6.19.10"
            },
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
              "vulnerable": true,
              "matchCriteriaId": "3599D100-DF0E-4F7B-90E5-56ECF94051B8",
              "versionEndExcluding": "7.0.11",
              "versionStartIncluding": "7.0.1"
            },
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:7.0:-:*:*:*:*:*:*",
              "vulnerable": true,
              "matchCriteriaId": "EF897730-3F1E-47A2-8B07-22535202C487"
            },
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:7.0:rc3:*:*:*:*:*:*",
              "vulnerable": true,
              "matchCriteriaId": "F666C8D8-6538-46D4-B318-87610DE64C34"
            },
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:7.0:rc4:*:*:*:*:*:*",
              "vulnerable": true,
              "matchCriteriaId": "02259FDA-961B-47BC-AE7F-93D7EC6E90C2"
            },
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:7.0:rc5:*:*:*:*:*:*",
              "vulnerable": true,
              "matchCriteriaId": "58A9FEFF-C040-420D-8F0A-BFDAAA1DF258"
            },
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:7.0:rc6:*:*:*:*:*:*",
              "vulnerable": true,
              "matchCriteriaId": "1D2315C0-D46F-4F85-9754-F9E5E11374A6"
            },
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:7.0:rc7:*:*:*:*:*:*",
              "vulnerable": true,
              "matchCriteriaId": "512EE3A8-A590-4501-9A94-5D4B268D6138"
            },
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:7.1:rc1:*:*:*:*:*:*",
              "vulnerable": true,
              "matchCriteriaId": "B1EF7059-E670-45F4-B422-54C40FA86390"
            },
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:7.1:rc2:*:*:*:*:*:*",
              "vulnerable": true,
              "matchCriteriaId": "0D38F0BF-A728-4133-A358-D44A2F7EE6D6"
            },
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:7.1:rc3:*:*:*:*:*:*",
              "vulnerable": true,
              "matchCriteriaId": "EC732D08-5F7B-46D9-B154-E60C7F4F0A97"
            },
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:7.1:rc4:*:*:*:*:*:*",
              "vulnerable": true,
              "matchCriteriaId": "E5910A9D-F60A-409A-B486-FE66BFEBA9B9"
            }
          ],
          "operator": "OR"
        }
      ]
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}