CVE-2025-40328
Unknown Unknown - Not Provided

BaseFortify

Publication date: 2025-12-09

Last updated on: 2025-12-09

Assigner: kernel.org

Description
In the Linux kernel, the following vulnerability has been resolved: smb: client: fix potential UAF in smb2_close_cached_fid() find_or_create_cached_dir() could grab a new reference after kref_put() had seen the refcount drop to zero but before cfid_list_lock is acquired in smb2_close_cached_fid(), leading to use-after-free. Switch to kref_put_lock() so cfid_release() is called with cfid_list_lock held, closing that gap.

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Meta Information

Published
2025-12-09
Last Modified
2025-12-09
Generated
2026-07-06
AI Q&A
2025-12-09
EPSS Evaluated
2026-07-05
NVD
CVE-2025-40328
EUVD
EUVD-2025-201874

Affected Vendors & Products

Showing 1 associated CPE
Vendor Product Version / Range
linux linux_kernel *

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Exploitability

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CWE ID Description
CWE-UNKNOWN

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Executive Summary

This vulnerability is a use-after-free (UAF) issue in the Linux kernel's SMB client code. Specifically, in the function smb2_close_cached_fid(), a reference count can drop to zero and the object can be freed, but before a lock (cfid_list_lock) is acquired, another reference might be grabbed. This timing gap can lead to accessing memory that has already been freed, causing undefined behavior or potential exploitation. The fix involves changing the code to hold the lock during the reference count decrement to prevent this race condition.

Impact Analysis

This use-after-free vulnerability could lead to system instability, crashes, or potentially allow an attacker to execute arbitrary code with kernel privileges if exploited. This could compromise the security and reliability of systems running the affected Linux kernel SMB client.

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