FKIE_CVE-2026-64108

Vulnerability from fkie_nvd - Published: 2026-07-19 16:17 - Updated: 2026-07-20 15:17
Severity
7.8 (High) - CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Summary
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 Fix it by flushing 'deferredclose_wq' before calling kill_anon_super. Fetch a reproducer in https://bugzilla.kernel.org/show_bug.cgi?id=221548.
References
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/5e7d9d0805e58fa3760894e73115b7a74024fd07
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/bdc349a87f1fb02c18c4071858a06542bfea783d
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/c68337442f03953237a94577beb468ab2662a851
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/c7364cea52531534676b9f7dbc0a477c11f4c050
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/e1ffa6cf662383f95816eed1b623429d82675e75
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/f2deaa2f409a4598eaa10f2a93a676c0632af248
Impacted products
Vendor Product Version
To clipboard 

{
  "affected": [
    {
      "affectedData": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "fs/smb/client/cifsfs.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "c7364cea52531534676b9f7dbc0a477c11f4c050",
              "status": "affected",
              "version": "708c276f516d27beaded7f372ac8111cee43926c",
              "versionType": "git"
            },
            {
              "lessThan": "bdc349a87f1fb02c18c4071858a06542bfea783d",
              "status": "affected",
              "version": "0629a1a187e424373364d681b42b101894bdb548",
              "versionType": "git"
            },
            {
              "lessThan": "f2deaa2f409a4598eaa10f2a93a676c0632af248",
              "status": "affected",
              "version": "0e4b8faaaebe3137bec5723ef2b3cb0437fb38fd",
              "versionType": "git"
            },
            {
              "lessThan": "5e7d9d0805e58fa3760894e73115b7a74024fd07",
              "status": "affected",
              "version": "f655467a9973f964b267871e5fef533ad5014494",
              "versionType": "git"
            },
            {
              "lessThan": "e1ffa6cf662383f95816eed1b623429d82675e75",
              "status": "affected",
              "version": "340cea84f691c5206561bb2e0147158fe02070be",
              "versionType": "git"
            },
            {
              "lessThan": "c68337442f03953237a94577beb468ab2662a851",
              "status": "affected",
              "version": "340cea84f691c5206561bb2e0147158fe02070be",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "30afc6ea72cc6cf7c8d579e79b64232801c38d08",
              "versionType": "git"
            },
            {
              "lessThan": "6.1.175",
              "status": "affected",
              "version": "6.1.167",
              "versionType": "semver"
            },
            {
              "lessThan": "6.6.142",
              "status": "affected",
              "version": "6.6.130",
              "versionType": "semver"
            },
            {
              "lessThan": "6.12.92",
              "status": "affected",
              "version": "6.12.78",
              "versionType": "semver"
            },
            {
              "lessThan": "6.18.34",
              "status": "affected",
              "version": "6.18.20",
              "versionType": "semver"
            },
            {
              "lessThan": "6.20",
              "status": "affected",
              "version": "6.19.10",
              "versionType": "semver"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "fs/smb/client/cifsfs.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "7.0"
            },
            {
              "lessThan": "7.0",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.1.*",
              "status": "unaffected",
              "version": "6.1.175",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.6.*",
              "status": "unaffected",
              "version": "6.6.142",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.92",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.34",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.0.*",
              "status": "unaffected",
              "version": "7.0.11",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.1",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "cveTags": [],
  "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-\u003edeferred) 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-\u003e__f_path = *path // dentry-\u003ed_lockref.count = 1\n   cifs_open\n    cifs_new_fileinfo\n     cfile-\u003edentry = dget(dentry) // dentry-\u003ed_lockref.count = 2\n close(fd)\n  __fput\n  cifs_close\n   queue_delayed_work(deferredclose_wq, cfile-\u003edeferred)\n  dput(dentry) // dentry-\u003ed_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(\u0026cifs_file-\u003eflist)\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-\u003ed_lockref.count = 1\n\t\t\t\t\t   cifsFileInfo_put_final\n\t\t\t\t\t    dput(cifs_file-\u003edentry)\n\t\t                            // dentry-\u003ed_lockref.count = 0\n\nFix it by flushing \u0027deferredclose_wq\u0027 before calling kill_anon_super.\n\nFetch a reproducer in https://bugzilla.kernel.org/show_bug.cgi?id=221548."
    }
  ],
  "id": "CVE-2026-64108",
  "lastModified": "2026-07-20T15:17:09.540",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "LOCAL",
          "availabilityImpact": "HIGH",
          "baseScore": 7.8,
          "baseSeverity": "HIGH",
          "confidentialityImpact": "HIGH",
          "integrityImpact": "HIGH",
          "privilegesRequired": "LOW",
          "scope": "UNCHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
          "version": "3.1"
        },
        "exploitabilityScore": 1.8,
        "impactScore": 5.9,
        "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "type": "Secondary"
      }
    ]
  },
  "published": "2026-07-19T16:17:52.100",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/5e7d9d0805e58fa3760894e73115b7a74024fd07"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/bdc349a87f1fb02c18c4071858a06542bfea783d"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/c68337442f03953237a94577beb468ab2662a851"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/c7364cea52531534676b9f7dbc0a477c11f4c050"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/e1ffa6cf662383f95816eed1b623429d82675e75"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/f2deaa2f409a4598eaa10f2a93a676c0632af248"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Received"
}



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