CVE-2026-97557

High

In the Linux kernel, the following vulnerability has been resolved: smb: client: avoid leaking refcount in cifs_queue_oplock_break() cifs_queue_oplock_break() unconditionally takes a reference on the target file before queueing cifs_oplock_break(). Only that work item decreases the reference counter again. If another oplock break arrives while that work is still queued, queue_work() will return false and not queue this second work item. As a result, we will never reach the point to drop the file reference again and are leaking this reference. This can be triggered when interacting with a slow-responding server. As a result, later unmount operations for this file system will fail with BUG: Dentry ... still in use (1) [unmount of cifs cifs] VFS: Busy inodes after unmount of cifs (cifs) kernel BUG at fs/super.c:777! Fix this by only incrementing the reference count if the work has been queued successfully. Taking it after queue_work() is safe because all three callers hold tcon->open_file_lock across the call and _cifsFileInfo_put() decrements under that same lock, so a worker that starts the handler in the window cannot drop the reference before it has been taken.

Package Linux Kernel
Published 2026-09-25
Last modified 2026-10-03
CVSS version 3.1
Patch available
Yes

CVSS 3.1 score

7.5

out of 10
High
Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
Low
Integrity
None
Availability
High
Vector string
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Affected versions

Linux kernel versions 3.16.72, 4.9.171, 4.14.114, 4.19.37, 5.0.10, 5.1 and later are affected. Fixed in 6.1.189, 6.6.158, 6.12.111, 6.18.53, 7.2.7, 7.3-rc3 and their respective stable series.

Affected from
≥ 3.16.72 ≥ 4.9.171 ≥ 4.14.114 ≥ 4.19.37 ≥ 5.0.10 ≥ 5.1
Fixed in
✓ 6.1.189 6.1.x ✓ 6.6.158 6.6.x ✓ 6.12.111 6.12.x ✓ 6.18.53 6.18.x ✓ 7.2.7 7.2.x ✓ 7.3-rc3

References

6 total
Showing 5 of 6 references View all on NVD

Frequently asked questions

  • What is CVE-2026-97557?

    CVE-2026-97557 is a High severity Linux kernel vulnerability with a CVSS score of 7.5 out of 10 . It affects Linux kernel versions from 3.16.72 onward and has been patched in 6.1.189, 6.6.158, 6.12.111 and others. CVE-2026-97557 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.

  • What is the CVSS score for CVE-2026-97557?

    CVE-2026-97557 has a CVSS score of 7.5 out of 10, rated High severity (CVSS 3.1). The vector string is CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H .

  • Is there a patch available for CVE-2026-97557?

    Yes. CVE-2026-97557 has been patched. Fixed versions include 6.1.189, 6.6.158, 6.12.111 and others. If you are running Linux kernel 3.16.72 or later up to the fix versions, apply the relevant patch for your kernel branch.

  • Is CVE-2026-97557 actively exploited?

    No. CVE-2026-97557 has not been confirmed as actively exploited. It is not listed in the CISA Known Exploited Vulnerabilities (KEV) catalog.

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