Description
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.
Published: 2026-09-25
Score: n/a
EPSS: n/a
KEV: No
Impact: n/a
Action: n/a
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Remediation

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History

Fri, 25 Sep 2026 10:30:00 +0000

Type Values Removed Values Added
Description 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.
Title smb: client: avoid leaking refcount when cifs_sb_tlink() fails
First Time appeared Linux
Linux linux Kernel
CPEs cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
Vendors & Products Linux
Linux linux Kernel
References

Subscriptions

Linux Linux Kernel
cve-icon MITRE

Status: PUBLISHED

Assigner: Linux

Published:

Updated: 2026-09-25T10:21:47.078Z

Reserved: 2026-09-24T16:01:01.154Z

Link: CVE-2026-97556

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Received

Published: 2026-09-25T11:17:06.077

Modified: 2026-09-25T11:17:06.077

Link: CVE-2026-97556

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-09-25T17:15:14Z

Weaknesses

No weakness.