Not yet scoredPublished Sep 25, 2026

CVE-2026-97556smb: client: avoid leaking refcount when cifs_sb_tlink() fails

Updated under an hour ago (Oct 26, 2026, 5:23 PM ET)

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Exploited in the last 30 days

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: Not yet scored
Weakness (CWE): Not given
Known exploited: Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days): Not loaded for this CVE
Assigned by: Linux
NVD analysis: Received
Record last updated: Oct 19, 2026
First seen by InfoSec Signals: Oct 9, 2026

Affected products

Affected products

Linux Linux linux:linux (from the name)	from 5ee28bcfbaacf289eb25c662a2862542ea6ce6a7 before 55c5f095d4df14271b238f826e1392fda7b6e60e; from e8f5f849ffce24490eb9449e98312b66c0dba76f before e9c5bcc88b8337157e480c85a6d2f326bc265012; from e8f5f849ffce24490eb9449e98312b66c0dba76f before 9ec991e148368e3207e98134c509a625097f7693; from e8f5f849ffce24490eb9449e98312b66c0dba76f before dd03fd658ea59821505e0e643b6b7cbdf51c4e1d; from e8f5f849ffce24490eb9449e98312b66c0dba76f before 1d1b0f1d812a4011a57bc6c70492c34a2e46c6dd; from e8f5f849ffce24490eb9449e98312b66c0dba76f before 23b26f4408ac3f35a482d2e5cf6fc865d4201b71; b99f490ea87ebcca3a429fd8837067feb56a4c7c; 6b67a6d2e50634fe127e656147c81915955e9f5e; and 3 more ranges	CNA record

References

References

https://git.kernel.org/stable/c/55c5f095d4df14271b238f826e1392fda7b6e60e
https://git.kernel.org/stable/c/e9c5bcc88b8337157e480c85a6d2f326bc265012
https://git.kernel.org/stable/c/9ec991e148368e3207e98134c509a625097f7693
https://git.kernel.org/stable/c/dd03fd658ea59821505e0e643b6b7cbdf51c4e1d
https://git.kernel.org/stable/c/1d1b0f1d812a4011a57bc6c70492c34a2e46c6dd
https://git.kernel.org/stable/c/23b26f4408ac3f35a482d2e5cf6fc865d4201b71

The CVE record on cve.org NVD's entry

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.