CVE-2026-97556
Received
Received - Intake
Reference Leak in Linux Kernel SMB Client
Vulnerability report for CVE-2026-97556, including description, CVSS score, EPSS score, affected products, exploitability, helpful resources, and attack-flow context.
Publication date: 2026-09-25
Last updated on: 2026-09-25
Assigner: kernel.org
Description
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.
CVSS Scores
EPSS Scores
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Meta Information
Affected Vendors & Products
Currently, no data is known.
Helpful Resources
Exploitability
CWE
KEV
| CWE ID | Description |
|---|---|
| CWE-UNKNOWN |
