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NVD / CVE Program· CNA Linux

CVE-2026-64108: cifs: Fix busy dentry used after unmounting

Noroxi assessment

Priority: Monitor (action score 31/100)

  • The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
  • Probability of exploitation in the next 30 days: 0.12% (FIRST EPSS).
  • Someone with local access to the system can trigger it. A low-privileged account is enough. No user action is required. No special conditions are required; it is repeatable.
  • Fixed version: Linux Linux 5e7d9d0805e58fa3760894e73115b7a74024fd07, 6.1.175, 6.12.92.

Low priority for now. Upgrade to Linux Linux 5e7d9d0805e58fa3760894e73115b7a74024fd07, 6.1.175, 6.12.92 or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

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.

HighCVSS 7.8 · v3.1—No exploit Fix available
Published
Jul 19, 2026
Updated
Aug 12, 2026
EPSS
0.1% · 2th percentile
CWE
—

Report tools

JSON

Action score

31

Monitor

Low priority for now.

CVSS
31 / 40 · 7.8 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.1%

CNA vs NVD score

NVD
—
CNA · Linux
7.8
NVD has not scored this yet; the score shown is the CNA’s.

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

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  • when EPSS rises 20 points in a week

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

VendorProduct
linuxlinux kernel

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

  • linux linux kernel6.1.167 and later · before 6.1.175
  • linux linux kernel6.6.130 and later · before 6.6.142
  • linux linux kernel6.12.78 and later · before 6.12.92
  • linux linux kernel6.18.20 and later · before 6.18.34
  • linux linux kernel6.19.10 and later · before 7.0
  • linux linux kernel7.0.1 and later · before 7.0.11
  • linux linux kernel7.0
  • linux linux kernel7.1

Versions reported by the vendor

Affected version ranges reported by the assigning authority (Linux). Independent of NVD's CPE analysis and usually ahead of it.

  • Linux Linux

    • 30afc6ea72cc6cf7c8d579e79b64232801c38d08, 7.0affected
    • 708c276f516d27beaded7f372ac8111cee43926c and later · before c7364cea52531534676b9f7dbc0a477c11f4c050affected · git
    • 0629a1a187e424373364d681b42b101894bdb548 and later · before bdc349a87f1fb02c18c4071858a06542bfea783daffected · git
    • 0e4b8faaaebe3137bec5723ef2b3cb0437fb38fd and later · before f2deaa2f409a4598eaa10f2a93a676c0632af248affected · git
    • f655467a9973f964b267871e5fef533ad5014494 and later · before 5e7d9d0805e58fa3760894e73115b7a74024fd07affected · git
    • 340cea84f691c5206561bb2e0147158fe02070be and later · before e1ffa6cf662383f95816eed1b623429d82675e75affected · git
    • 340cea84f691c5206561bb2e0147158fe02070be and later · before c68337442f03953237a94577beb468ab2662a851affected · git
    • 6.1.167 and later · before 6.1.175affected · semver
    • 6.6.130 and later · before 6.6.142affected · semver
    • 6.12.78 and later · before 6.12.92affected · semver

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
Debian:12linuxbefore 6.1.176-16.1.176-1
Debian:13linuxbefore 6.12.94-16.12.94-1
Debian:14linuxbefore 7.0.12-17.0.12-1

Same product

linux: all records

Other highest-scoring records for the same primary product.

  • CVE-2026-31431crypto: algif_aead - Revert to operating out-of-placeKEV
    90Now
  • CVE-2022-0847A flaw was found in the way the "flags" member of the new pipe buffer structure was lacking proper initialization in copy_page_to_iter_pipe KEV
    89Now
  • CVE-2021-22555Heap Out-Of-Bounds Write in Netfilter IP6T_SO_SET_REPLACEKEV
    85Now

Published before and after this one in the same product

  • ← EarlierCVE-2026-64105Jul 19, 2026 · KVM: arm64: vgic: Free private_irqs when init fails after allocation
    22Monitor
  • ← EarlierCVE-2026-64107Jul 19, 2026 · ASoC: codecs: pcm512x: fix null-ptr dereference in pcm512x_overclock_xxx_put()
    22Monitor
  • Later →CVE-2026-64110Jul 19, 2026 · igc: fix potential skb leak in igc_fpe_xmit_smd_frame()
    22Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
Linux Linux5e7d9d0805e58fa3760894e73115b7a74024fd07Vendor (CNA)
Linux Linux6.1.175Vendor (CNA)
Linux Linux6.12.92Vendor (CNA)
Linux Linux6.18.34Vendor (CNA)
Linux Linux6.20Vendor (CNA)
Linux Linux6.6.142Vendor (CNA)
Linux Linuxbdc349a87f1fb02c18c4071858a06542bfea783dVendor (CNA)
Linux Linuxc68337442f03953237a94577beb468ab2662a851Vendor (CNA)
Linux Linuxc7364cea52531534676b9f7dbc0a477c11f4c050Vendor (CNA)
Linux Linuxe1ffa6cf662383f95816eed1b623429d82675e75Vendor (CNA)
Linux Linuxf2deaa2f409a4598eaa10f2a93a676c0632af248Vendor (CNA)
debian:linux6.1.176-1 · Debian:12Package registry (OSV)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

EPSS, last 120 days

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

No commit or PR link among the references.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

No credits in the CNA record.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

No nightly-computed relations.

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

Technical details

Attack conditions

  • Someone with local access to the system can trigger it.
  • A low-privileged account is enough.
  • No user action is required.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
high · data can be read
Integrity
high · data or configuration can be modified
Availability
high · the service can be disrupted
Attack vector
Local
Attack complexity
Low
Privileges required
Low
User interaction
None
Scope
Unchanged
Confidentiality impact
High
Integrity impact
High
Availability impact
High

Weakness class (CWE)

—

CVSS vector

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

nvd-secondary

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

MITRE has no CAPEC/ATT&CK mapping for this CWE.

Change log

  1. Fix✗ → ✓

For records you follow, these changes also arrive as notifications. →

References

Show all references (5 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records