CVE-2025-37954Network attack vector

Service interruption via cached-directory reference leak

Published May 20, 2025 · Updated Aug 5, 2026

A race in the Linux kernel SMB client allows remote attackers to exhaust kernel resources and interrupt service through lease breaks. The find_or_create_cached_dir function can return a valid cached-file identifier that queued lease-break work invalidates before open_cached_dir checks it, causing the identifier to be treated as newly created and its dentry reference to leak. Reachability requires an SMB connection that delivers a lease break during cached-directory lookup; repeated races can accumulate leaked references until kernel resources are exhausted.

CVSS severity7.5
High
EPSS probability0.34%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

A race in the Linux kernel SMB client allows remote attackers to exhaust kernel resources and interrupt service through lease breaks. The find_or_create_cached_dir function can return a valid cached-file identifier that queued lease-break work invalidates before open_cached_dir checks it, causing the identifier to be treated as newly created and its dentry reference to leak. Reachability requires an SMB connection that delivers a lease break during cached-directory lookup; repeated races can accumulate leaked references until kernel resources are exhausted.

The record

CVE
CVE-2025-37954
Published
May 20, 2025
Updated
Aug 5, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. May 20, 2025CVE publishedPublication date reported by the CVE source.
  2. Aug 5, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=436be190fbf81e5d84040dabf9cb7be06a94dc5d
  2. Affected versionversion=6.5.10 <6.6
  3. Affected versionversion=6.6
  4. Affected versionversion=81ba10959970d15c388bf29866b01b62f387e6a3 <2407265dc32bc8cc45b62a612c2a214ba9038e8b
  5. Affected versionversion=81ba10959970d15c388bf29866b01b62f387e6a3 <2ed98e89ebc2e1bc73534dc3c18cb7843a889ff9
  6. Affected versionversion=81ba10959970d15c388bf29866b01b62f387e6a3 <3ca02e63edccb78ef3659bebc68579c7224a6ca2
  7. Affected versionversion=81ba10959970d15c388bf29866b01b62f387e6a3 <571dcf3d27b24800c171aea7b5e04ff06d10e2e9

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=436be190fbf81e5d84040dabf9cb7be06a94dc5d; version=6.5.10 <6.6; version=6.6; version=81ba10959970d15c388bf29866b01b62f387e6a3 <2407265dc32bc8cc45b62a612c2a214ba9038e8b; version=81ba10959970d15c388bf29866b01b62f387e6a3 <2ed98e89ebc2e1bc73534dc3c18cb7843a889ff9; version=81ba10959970d15c388bf29866b01b62f387e6a3 <3ca02e63edccb78ef3659bebc68579c7224a6ca2; version=81ba10959970d15c388bf29866b01b62f387e6a3 <571dcf3d27b24800c171aea7b5e04ff06d10e2e9

Published CVSS scores

5.5NIST NVDCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
7.5kernel.orgCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

T1499.004Application or System Exploitation

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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