CVE-2025-68226Network attack vector

Kernel denial of service via cached-directory use-after-free

Published Dec 16, 2025 · Updated Dec 16, 2025

Use-after-free in the Linux SMB client 6.17.8 through 6.17.9 allows remote attackers to interrupt the kernel through SMB activity. cfids_invalidation_worker() directly calls kref_put() on a cached-directory reference instead of close_cached_dir(), permitting later work to access the freed object. Reachability requires the SMB client path and interaction with an SMB share; successful exploitation destabilizes or crashes the host kernel.

CVSS severity8.8
High
EPSS probability0.35%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Use-after-free in the Linux SMB client 6.17.8 through 6.17.9 allows remote attackers to interrupt the kernel through SMB activity. cfids_invalidation_worker() directly calls kref_put() on a cached-directory reference instead of close_cached_dir(), permitting later work to access the freed object. Reachability requires the SMB client path and interaction with an SMB share; successful exploitation destabilizes or crashes the host kernel.

The record

CVE
CVE-2025-68226
Published
Dec 16, 2025
Updated
Dec 16, 2025
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
CWE-911, T1499
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Dec 16, 2025CVE publishedPublication date reported by the CVE source.
  2. Dec 16, 2025Record 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=6.17.8 <6.17.10
  2. Affected versionversion=bdb596ceb4b7c3f28786a33840263728217fbcf5 <abd29b6e17a918fdd68352ce4813e167acc8727e

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=6.17.8 <6.17.10; version=bdb596ceb4b7c3f28786a33840263728217fbcf5 <abd29b6e17a918fdd68352ce4813e167acc8727e

Published CVSS scores

8.8Linux CNACVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
5.5Red HatCVSS:3.1/AV:L/AC:L/PR:L/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

CWE-911Improper Update of Reference Count
T1499Endpoint Denial of Service

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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