CVE-2026-97556
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.
Affected versions
Linux kernel versions
6.1.47,
5.15.128,
6.4.12,
6.5
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.
References
6 totalFrequently asked questions
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What is CVE-2026-97556?
CVE-2026-97556 is a unscored severity Linux kernel vulnerability . It affects Linux kernel versions from 6.1.47 onward and has been patched in 6.1.189, 6.6.158, 6.12.111 and others. CVE-2026-97556 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.
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Is there a patch available for CVE-2026-97556?
Yes. CVE-2026-97556 has been patched. Fixed versions include 6.1.189, 6.6.158, 6.12.111 and others. If you are running Linux kernel 6.1.47 or later up to the fix versions, apply the relevant patch for your kernel branch.
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Is CVE-2026-97556 actively exploited?
No. CVE-2026-97556 has not been confirmed as actively exploited. It is not listed in the CISA Known Exploited Vulnerabilities (KEV) catalog.