---
id: CVE-2025-40328
title: |-
  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 bu…
summary: |-
  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 bu…
severity: high
cvss: 8.8
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H'
published: '2025-12-09'
updated: '2026-10-15'
sourceUpdated: '2026-10-15T19:10:00.173'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2025-40328'
references:
  - url: 'https://git.kernel.org/stable/c/065bd62412271a2d734810dd50336cae88c54427'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/734e99623c5b65bf2c03e35978a0b980ebc3c2f8'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/bdb596ceb4b7c3f28786a33840263728217fbcf5'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/cb52d9c86d70298de0ab7c7953653898cbc0efd6'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
tags:
  - nvd
epss: 0.00461
epssPercentile: 0.38384
ingestedAt: '2026-10-15T19:25:46.340Z'
---

## Overview

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.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.