CVE-2026-64108 (GCVE-0-2026-64108)

Vulnerability from cvelistv5 – Published: 2026-07-19 15:40 – Updated: 2026-07-20 13:43
VLAI
Title
cifs: Fix busy dentry used after unmounting
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.
Severity
7.8 (High)
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Assigner
References
Impacted products
Vendor Product Version
Linux Linux Affected: 708c276f516d27beaded7f372ac8111cee43926c , < c7364cea52531534676b9f7dbc0a477c11f4c050 (git)
Affected: 0629a1a187e424373364d681b42b101894bdb548 , < bdc349a87f1fb02c18c4071858a06542bfea783d (git)
Affected: 0e4b8faaaebe3137bec5723ef2b3cb0437fb38fd , < f2deaa2f409a4598eaa10f2a93a676c0632af248 (git)
Affected: f655467a9973f964b267871e5fef533ad5014494 , < 5e7d9d0805e58fa3760894e73115b7a74024fd07 (git)
Affected: 340cea84f691c5206561bb2e0147158fe02070be , < e1ffa6cf662383f95816eed1b623429d82675e75 (git)
Affected: 340cea84f691c5206561bb2e0147158fe02070be , < c68337442f03953237a94577beb468ab2662a851 (git)
Affected: 30afc6ea72cc6cf7c8d579e79b64232801c38d08 (git)
Affected: 6.1.167 , < 6.1.175 (semver)
Affected: 6.6.130 , < 6.6.142 (semver)
Affected: 6.12.78 , < 6.12.92 (semver)
Affected: 6.18.20 , < 6.18.34 (semver)
Affected: 6.19.10 , < 6.20 (semver)
Create a notification for this product.
Linux Linux Affected: 7.0
Unaffected: 0 , < 7.0 (semver)
Unaffected: 6.1.175 , ≤ 6.1.* (semver)
Unaffected: 6.6.142 , ≤ 6.6.* (semver)
Unaffected: 6.12.92 , ≤ 6.12.* (semver)
Unaffected: 6.18.34 , ≤ 6.18.* (semver)
Unaffected: 7.0.11 , ≤ 7.0.* (semver)
Unaffected: 7.1 , ≤ * (original_commit_for_fix)
Create a notification for this product.
Show details on NVD website
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          "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."
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          "url": "https://git.kernel.org/stable/c/c68337442f03953237a94577beb468ab2662a851"
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// 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.\"}],\"affected\":[{\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"affectedData\":[{\"vendor\":\"Linux\",\"product\":\"Linux\",\"defaultStatus\":\"unaffected\",\"programFiles\":[\"fs/smb/client/cifsfs.c\"],\"repo\":\"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\"versions\":[{\"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\",\"status\":\"affected\"}]},{\"vendor\":\"Linux\",\"product\":\"Linux\",\"defaultStatus\":\"affected\",\"programFiles\":[\"fs/smb/client/cifsfs.c\"],\"repo\":\"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\"versions\":[{\"version\":\"7.0\",\"status\":\"affected\"},{\"version\":\"0\",\"lessThan\":\"7.0\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"6.1.175\",\"lessThanOrEqual\":\"6.1.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"6.6.142\",\"lessThanOrEqual\":\"6.6.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"6.12.92\",\"lessThanOrEqual\":\"6.12.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"6.18.34\",\"lessThanOrEqual\":\"6.18.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"7.0.11\",\"lessThanOrEqual\":\"7.0.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"7.1\",\"lessThanOrEqual\":\"*\",\"versionType\":\"original_commit_for_fix\",\"status\":\"unaffected\"}]}]}],\"metrics\":{\"cvssMetricV31\":[{\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"type\":\"Secondary\",\"cvssData\":{\"version\":\"3.1\",\"vectorString\":\"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H\",\"baseScore\":7.8,\"baseSeverity\":\"HIGH\",\"attackVector\":\"LOCAL\",\"attackComplexity\":\"LOW\",\"privilegesRequired\":\"LOW\",\"userInteraction\":\"NONE\",\"scope\":\"UNCHANGED\",\"confidentialityImpact\":\"HIGH\",\"integrityImpact\":\"HIGH\",\"availabilityImpact\":\"HIGH\"},\"exploitabilityScore\":1.8,\"impactScore\":5.9}]},\"references\":[{\"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\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"}]}}",
    "redhat_vex": {
      "aggregate_severity": "None",
      "current_release_date": "2026-07-21T08:07:39+00:00",
      "cve": "CVE-2026-64108",
      "id": "CVE-2026-64108",
      "initial_release_date": "2026-07-19T00:00:00+00:00",
      "product_status:known_not_affected": "274",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "kernel: cifs: Fix busy dentry used after unmounting",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-64108.json",
      "version": "3"
    }
  }
}



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