Linux Kernel up to 6.17.9 smb cfids_invalidation_worker use after free

CVSS Meta Temp Score
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CTI Interest Score
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7.6$0-$5k0.00

Summaryinfo

A vulnerability has been found in Linux Kernel up to 6.17.9 and classified as critical. The affected element is the function cfids_invalidation_worker of the component smb. The manipulation leads to use after free. This vulnerability is referenced as CVE-2025-68226. No exploit is available. The affected component should be upgraded.

Detailsinfo

A vulnerability was found in Linux Kernel up to 6.17.9. It has been rated as critical. This issue affects the function cfids_invalidation_worker of the component smb. The manipulation with an unknown input leads to a use after free vulnerability. Using CWE to declare the problem leads to CWE-416. Referencing memory after it has been freed can cause a program to crash, use unexpected values, or execute code. Impacted is confidentiality, integrity, and availability. The summary by CVE is:

In the Linux kernel, the following vulnerability has been resolved: smb: client: fix incomplete backport in cfids_invalidation_worker() The previous commit bdb596ceb4b7 ("smb: client: fix potential UAF in smb2_close_cached_fid()") was an incomplete backport and missed one kref_put() call in cfids_invalidation_worker() that should have been converted to close_cached_dir().

It is possible to read the advisory at git.kernel.org. The identification of this vulnerability is CVE-2025-68226 since 12/16/2025. The exploitation is known to be easy. Technical details of the vulnerability are known, but there is no available exploit. The pricing for an exploit might be around USD $0-$5k at the moment (estimation calculated on 02/21/2026).

The vulnerability scanner Nessus provides a plugin with the ID 278931 (Linux Distros Unpatched Vulnerability : CVE-2025-68226), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 6.17.10 eliminates this vulnerability. Applying the patch abd29b6e17a918fdd68352ce4813e167acc8727e is able to eliminate this problem. The bugfix is ready for download at git.kernel.org. The best possible mitigation is suggested to be upgrading to the latest version.

The vulnerability is also documented in the databases at Tenable (278931) and CERT Bund (WID-SEC-2025-2868). Be aware that VulDB is the high quality source for vulnerability data.

Affected

  • Debian Linux
  • Amazon Linux 2
  • Red Hat Enterprise Linux
  • Ubuntu Linux
  • SUSE Linux
  • Oracle Linux
  • SUSE openSUSE
  • RESF Rocky Linux
  • Open Source Linux Kernel

Productinfo

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Vendor

Name

Version

License

Website

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 8.0
VulDB Meta Temp Score: 7.6

VulDB Base Score: 8.0
VulDB Temp Score: 7.6
VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv2info

AVACAuCIA
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VectorComplexityAuthenticationConfidentialityIntegrityAvailability
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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Use after free
CWE: CWE-416 / CWE-119
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Partially

Availability: 🔒
Status: Not defined

EPSS Score: 🔒
EPSS Percentile: 🔒

Price Prediction: 🔍
Current Price Estimation: 🔒

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Nessus ID: 278931
Nessus Name: Linux Distros Unpatched Vulnerability : CVE-2025-68226

Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: Kernel 6.17.10
Patch: abd29b6e17a918fdd68352ce4813e167acc8727e

Timelineinfo

12/16/2025 Advisory disclosed
12/16/2025 +0 days CVE reserved
12/16/2025 +0 days VulDB entry created
02/21/2026 +67 days VulDB entry last update

Sourcesinfo

Vendor: kernel.org

Advisory: git.kernel.org
Status: Confirmed

CVE: CVE-2025-68226 (🔒)
GCVE (CVE): GCVE-0-2025-68226
GCVE (VulDB): GCVE-100-336815
CERT Bund: WID-SEC-2025-2868 - Linux Kernel: Mehrere Schwachstellen

Entryinfo

Created: 12/16/2025 16:12
Updated: 02/21/2026 16:36
Changes: 12/16/2025 16:12 (59), 12/17/2025 16:22 (2), 01/20/2026 01:52 (7), 02/03/2026 09:18 (1), 02/21/2026 16:36 (1)
Complete: 🔍
Cache ID: 216::103

Be aware that VulDB is the high quality source for vulnerability data.

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