cifs: Fix busy dentry used after unmounting

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-64108
StatePUBLISHED
AssignerLinux
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-07-19 16:17:52 UTC
Updated2026-08-12 15:14:14 UTC
DescriptionIn 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.

Risk And Classification

Primary CVSS: v3.1 7.8 HIGH from 416baaa9-dc9f-4396-8d5f-8c081fb06d67

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

EPSS: 0.001290000 probability, percentile 0.029680000 (date 2026-08-02)

Problem Types: NVD-CWE-noinfo

VersionSourceTypeScoreSeverityVector
3.1416baaa9-dc9f-4396-8d5f-8c081fb06d67Secondary7.8HIGHCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
3.1CNADECLARED7.8HIGHCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

CVSS v3.1 Breakdown

Attack Vector
Local
Attack Complexity
Low
Privileges Required
Low
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

NVD Known Affected Configurations (CPE 2.3)

TypeVendorProductVersionUpdateEditionLanguage
Operating System Linux Linux Kernel All All All All

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Linux Linux affected 708c276f516d27beaded7f372ac8111cee43926c c7364cea52531534676b9f7dbc0a477c11f4c050 git Not specified
CNA Linux Linux affected 0629a1a187e424373364d681b42b101894bdb548 bdc349a87f1fb02c18c4071858a06542bfea783d git Not specified
CNA Linux Linux affected 0e4b8faaaebe3137bec5723ef2b3cb0437fb38fd f2deaa2f409a4598eaa10f2a93a676c0632af248 git Not specified
CNA Linux Linux affected f655467a9973f964b267871e5fef533ad5014494 5e7d9d0805e58fa3760894e73115b7a74024fd07 git Not specified
CNA Linux Linux affected 340cea84f691c5206561bb2e0147158fe02070be e1ffa6cf662383f95816eed1b623429d82675e75 git Not specified
CNA Linux Linux affected 340cea84f691c5206561bb2e0147158fe02070be c68337442f03953237a94577beb468ab2662a851 git Not specified
CNA Linux Linux affected 30afc6ea72cc6cf7c8d579e79b64232801c38d08 git Not specified
CNA Linux Linux affected 6.1.167 6.1.175 semver Not specified
CNA Linux Linux affected 6.6.130 6.6.142 semver Not specified
CNA Linux Linux affected 6.12.78 6.12.92 semver Not specified
CNA Linux Linux affected 6.18.20 6.18.34 semver Not specified
CNA Linux Linux affected 6.19.10 6.20 semver Not specified
CNA Linux Linux affected 7.0 Not specified
CNA Linux Linux unaffected 7.0 semver Not specified
CNA Linux Linux unaffected 6.1.175 6.1.* semver Not specified
CNA Linux Linux unaffected 6.6.142 6.6.* semver Not specified
CNA Linux Linux unaffected 6.12.92 6.12.* semver Not specified
CNA Linux Linux unaffected 6.18.34 6.18.* semver Not specified
CNA Linux Linux unaffected 7.0.11 7.0.* semver Not specified
CNA Linux Linux unaffected 7.1 * original_commit_for_fix Not specified

References

ReferenceSourceLinkTags
git.kernel.org/stable/c/c7364cea52531534676b9f7dbc0a477c11f4c050 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org Patch
git.kernel.org/stable/c/bdc349a87f1fb02c18c4071858a06542bfea783d 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org Patch
git.kernel.org/stable/c/e1ffa6cf662383f95816eed1b623429d82675e75 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org Patch
git.kernel.org/stable/c/c68337442f03953237a94577beb468ab2662a851 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org Patch
git.kernel.org/stable/c/5e7d9d0805e58fa3760894e73115b7a74024fd07 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org Patch
git.kernel.org/stable/c/f2deaa2f409a4598eaa10f2a93a676c0632af248 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org Patch
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