smb: client: avoid leaking refcount in cifs_queue_oplock_break()

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-97557
StatePUBLISHED
AssignerLinux
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-09-25 11:17:06 UTC
Updated2026-09-25 15:17:58 UTC
DescriptionIn 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.

Risk And Classification

Primary CVSS: v3.1 7.5 HIGH from 416baaa9-dc9f-4396-8d5f-8c081fb06d67

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

EPSS: 0.006030000 probability, percentile 0.467380000 (date 2026-09-27)

VersionSourceTypeScoreSeverityVector
3.1416baaa9-dc9f-4396-8d5f-8c081fb06d67Secondary7.5HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
3.1CNADECLARED7.5HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

CVSS v3.1 Breakdown

Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Linux Linux affected b98749cac4a695f084a5ff076f4510b23e353ecd af0193bbf1ac8c0f67f972998b0cc629d6116cf6 git Not specified
CNA Linux Linux affected b98749cac4a695f084a5ff076f4510b23e353ecd 2ed2c29dd9593637cfa25ac1eb23241b20202778 git Not specified
CNA Linux Linux affected b98749cac4a695f084a5ff076f4510b23e353ecd dfe7b750c7e069873a8a57a11c816831a235618a git Not specified
CNA Linux Linux affected b98749cac4a695f084a5ff076f4510b23e353ecd 9f2e63f1b2d5fc5b5423424902c091123e220e7e git Not specified
CNA Linux Linux affected 2429fcf06d3cb962693868ab0a927c9038f12a2d git Not specified
CNA Linux Linux affected 1ee4f2d7cdcd4508cc3cbe3b2622d7177b89da12 git Not specified
CNA Linux Linux affected 53fc31a4853e30d6e8f142b824f724da27ff3e40 git Not specified
CNA Linux Linux affected 8092ecc306d81186a64cda42411121f4d35aaff4 git Not specified
CNA Linux Linux affected ebac4d0adf68f8962bd82fcf483936edd6ec095b git Not specified
CNA Linux Linux affected 3.16.72 3.17 semver Not specified
CNA Linux Linux affected 4.9.171 4.10 semver Not specified
CNA Linux Linux affected 4.14.114 4.15 semver Not specified
CNA Linux Linux affected 4.19.37 4.20 semver Not specified
CNA Linux Linux affected 5.0.10 5.1 semver Not specified
CNA Linux Linux affected 5.1 Not specified
CNA Linux Linux unaffected 5.1 semver Not specified
CNA Linux Linux unaffected 6.12.111 6.12.* semver Not specified
CNA Linux Linux unaffected 6.18.53 6.18.* semver Not specified
CNA Linux Linux unaffected 7.2.7 7.2.* semver Not specified
CNA Linux Linux unaffected 7.3-rc3 * original_commit_for_fix Not specified

References

ReferenceSourceLinkTags
git.kernel.org/stable/c/af0193bbf1ac8c0f67f972998b0cc629d6116cf6 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/2ed2c29dd9593637cfa25ac1eb23241b20202778 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/9f2e63f1b2d5fc5b5423424902c091123e220e7e 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/dfe7b750c7e069873a8a57a11c816831a235618a 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
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