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NVD / CVE Program· CNA Linux

CVE-2025-37954: smb: client: Avoid race in open_cached_dir with lease breaks

MediumCVSS 5.5 · v3.1—No exploit Fix available

Noroxi assessment

Priority: Monitor (action score 22/100)

  • 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: 0.36% (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.
  • According to CISA the attack is automatable: targets can be found by mass scanning.
  • Fixed version: Linux Linux 2407265dc32bc8cc45b62a612c2a214ba9038e8b, 2ed98e89ebc2e1bc73534dc3c18cb7843a889ff9, 3ca02e63edccb78ef3659bebc68579c7224a6ca2; azl3 kernel 6.6.85.1-4 on Azure Linux 3.0 CBL-Mariner Releases; Azure Linux 3.0 ARM 6.6.92.2-1.
  • Severity is disputed: the assigning authority (CNA) scores it 7.5, NVD 5.5.

Low priority for now. Upgrade to Linux Linux 2407265dc32bc8cc45b62a612c2a214ba9038e8b, 2ed98e89ebc2e1bc73534dc3c18cb7843a889ff9, 3ca02e63edccb78ef3659bebc68579c7224a6ca2; azl3 kernel 6.6.85.1-4 on Azure Linux 3.0 CBL-Mariner Releases; Azure Linux 3.0 ARM 6.6.92.2-1 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: smb: client: Avoid race in open_cached_dir with lease breaks A pre-existing valid cfid returned from find_or_create_cached_dir might race with a lease break, meaning open_cached_dir doesn't consider it valid, and thinks it's newly-constructed. This leaks a dentry reference if the allocation occurs before the queued lease break work runs. Avoid the race by extending holding the cfid_list_lock across find_or_create_cached_dir and when the result is checked.

Published
May 20, 2025
Updated
Oct 15, 2026
EPSS
0.3% · 30th percentile
CWE
—

Report tools

JSON

Action score

22

Monitor

Low priority for now.

CVSS
22 / 40 · 5.5 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.3%

CISA SSVC decision

Exploitation
none
Automatable
yes
Technical impact
partial

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD
5.5
CNA · Linux
7.5
2.0 point gap

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

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

Get told when this record changes

  • Not in KEV: no record of exploitation in the wild
  • No public exploit code on record
  • A fix has been released

If any of these changes, we'll tell you in the daily email digest.

Follow CVE-2025-37954

When you'll hear from us

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  • when exploit code appears or is weaponized
  • when the record is updated (including a fixed version)
  • 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

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

    • 436be190fbf81e5d84040dabf9cb7be06a94dc5d, 6.6affected
    • 81ba10959970d15c388bf29866b01b62f387e6a3 and later · before 2ed98e89ebc2e1bc73534dc3c18cb7843a889ff9affected · git
    • 81ba10959970d15c388bf29866b01b62f387e6a3 and later · before 571dcf3d27b24800c171aea7b5e04ff06d10e2e9affected · git
    • 81ba10959970d15c388bf29866b01b62f387e6a3 and later · before 2407265dc32bc8cc45b62a612c2a214ba9038e8baffected · git
    • 81ba10959970d15c388bf29866b01b62f387e6a3 and later · before 3ca02e63edccb78ef3659bebc68579c7224a6ca2affected · git
    • 6.5.10 and later · before 6.6affected · semver
    • before 6.6not affected · semver
    • 6.6.91 and later · up to and including 6.6.*not affected · semver
    • 6.12.29 and later · up to and including 6.12.*not affected · semver
    • 6.14.7 and later · up to and including 6.14.*not affected · semver
Affected versions · NVD (4)

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

  • linux linux kernelbefore 6.6.91
  • linux linux kernel6.7 and later · before 6.12.29
  • linux linux kernel6.13 and later · before 6.14.7
  • linux linux kernel6.15

Package-level exposure

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

EcosystemPackageAffected rangeFix
Debian:13linuxbefore 6.12.29-16.12.29-1

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-2025-37949May 20, 2025 · xenbus: Use kref to track req lifetime
    22Monitor
  • ← EarlierCVE-2025-37952May 20, 2025 · ksmbd: Fix UAF in __close_file_table_ids
    31Monitor
  • Later →CVE-2025-37956May 20, 2025 · ksmbd: prevent rename with empty string
    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 Linux2407265dc32bc8cc45b62a612c2a214ba9038e8bVendor (CNA)
Linux Linux2ed98e89ebc2e1bc73534dc3c18cb7843a889ff9Vendor (CNA)
Linux Linux3ca02e63edccb78ef3659bebc68579c7224a6ca2Vendor (CNA)
Linux Linux571dcf3d27b24800c171aea7b5e04ff06d10e2e9Vendor (CNA)
Linux Linux6.6Vendor (CNA)
azl3 kernel 6.6.85.1-4 on Azure Linux 3.0CBL-Mariner ReleasesMicrosoft (MSRC)
Azure Linux 3.0 ARM6.6.92.2-1 · kernelMicrosoft (MSRC)
Azure Linux 3.0 x646.6.92.2-1 · kernelMicrosoft (MSRC)
debian:linux6.12.29-1 · Debian:13Package 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.

Not on record for this CVE: EPSS history · patch commit or PR link · researcher credit · variant or chain candidate · public bounty program.

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

Weakness class (CWE)

—

CVSS vector

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

nvd-primary

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.

References

Show all references (3 more)

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

All records