---
id: CVE-2026-97556
title: |-
  In the Linux kernel, the following vulnerability has been resolved:

  smb: client: avoid leaking refcount when cifs_sb_tlink() fails

  cifs_oplock_break() takes over the reference that
  cifs_queue_oplock_break() acquired when it queued the …
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  smb: client: avoid leaking refcount when cifs_sb_tlink() fails

  cifs_oplock_break() takes over the reference that
  cifs_queue_oplock_break() acquired when it queued the …
severity: none
vendor: Linux
product: Linux
affected:
  - >-
    Linux >= e8f5f849ffce24490eb9449e98312b66c0dba76f <
    9ec991e148368e3207e98134c509a625097f7693
  - >-
    Linux >= e8f5f849ffce24490eb9449e98312b66c0dba76f <
    dd03fd658ea59821505e0e643b6b7cbdf51c4e1d
  - >-
    Linux >= e8f5f849ffce24490eb9449e98312b66c0dba76f <
    1d1b0f1d812a4011a57bc6c70492c34a2e46c6dd
  - >-
    Linux >= e8f5f849ffce24490eb9449e98312b66c0dba76f <
    23b26f4408ac3f35a482d2e5cf6fc865d4201b71
  - Linux b99f490ea87ebcca3a429fd8837067feb56a4c7c
  - Linux 5ee28bcfbaacf289eb25c662a2862542ea6ce6a7
  - Linux 6b67a6d2e50634fe127e656147c81915955e9f5e
  - Linux >= 5.15.128 < 5.16
  - Linux >= 6.1.47 < 6.2
  - Linux >= 6.4.12 < 6.5
  - Linux 6.5
published: '2026-09-25'
updated: '2026-09-25'
sourceUpdated: '2026-09-25T11:17:06.077'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-97556'
references:
  - url: 'https://git.kernel.org/stable/c/1d1b0f1d812a4011a57bc6c70492c34a2e46c6dd'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/23b26f4408ac3f35a482d2e5cf6fc865d4201b71'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/9ec991e148368e3207e98134c509a625097f7693'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/dd03fd658ea59821505e0e643b6b7cbdf51c4e1d'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
tags:
  - nvd
  - cve.org
ingestedAt: '2026-09-25T11:06:38.916Z'
---

## Overview

In the Linux kernel, the following vulnerability has been resolved:

smb: client: avoid leaking refcount when cifs_sb_tlink() fails

cifs_oplock_break() takes over the reference that
cifs_queue_oplock_break() acquired when it queued the work, and drops it
with _cifsFileInfo_put() once the break has been processed.

Only in setups with "-o multiuser", cifs_sb_tlink() may fail, at which
point cifs_oplock_break() returns without putting the file reference,
mirroring the reference leak we already fixed in the companion patch to
cifs_queue_oplock_break().

This would trigger a crash due to busy inodes on the next unmount:

  BUG: Dentry ... still in use (1) [unmount of cifs cifs]
  VFS: Busy inodes after unmount of cifs (cifs)

Drop the reference on that path as well. Doing so before the out label
mirrors the normal path, which also puts the reference before
cifs_done_oplock_break().

Found by Sashiko code review. The failure path was not exercised at
runtime.

## Remediation

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