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VulnerabilityPublished Updated

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

Source GCVE Database

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Authoritative record:CVE-2026-97556· Medium

Not known to be exploited · fixed in f1fd8a84181b3af03c508e0b02b4877945dd070a : update Linux kernel when convenient.

Data as of 30 Oct 2026, 17:33 UTC

Severity
Medium

Rated Medium by Threat Radar's AI analysis · CVSS not yet scored by NVD

Thin evidence

One scorer or none
Patch
Available – fixed in f1fd8a84181b3af03c508e0b02b4877945dd070a, e9c5bcc88b8337157e480c85a6d2f326bc265012, dd03fd658ea59821505e0e643b6b7cbdf51c4e1d +7

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 25 Sep 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponized: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 30 Oct 2026.

What to do

Upgrade to a fixed release listed under Affected software.

Affected software

ProductAffectedFixed in
LinuxLinuxAffected
  • >=5.15.128 <5.15.224
  • >=6.1.47 <6.1.189
  • >=6.4.12 <6.5
Fixed in
  • f1fd8a84181b3af03c508e0b02b4877945dd070a
  • e9c5bcc88b8337157e480c85a6d2f326bc265012
  • dd03fd658ea59821505e0e643b6b7cbdf51c4e1d
  • 55c5f095d4df14271b238f826e1392fda7b6e60e
  • 23b26f4408ac3f35a482d2e5cf6fc865d4201b71
  • 9ec991e148368e3207e98134c509a625097f7693
  • 6.5
  • 6.1.189
  • 5.15.224
  • 1d1b0f1d812a4011a57bc6c70492c34a2e46c6dd
LinuxLinuxAffected
  • =6.5
Fixed in–

AI-suggested

A fix has been applied to the Linux kernel to properly drop the leaked reference in the failure path of cifs_sb_tlink(). Users should update to the fixed kernel version once available. No additional mitigations are indicated.

Description

A reference count leak in the Linux kernel's SMB client code was fixed. The issue occurred when cifs_sb_tlink() failed in multiuser setups, causing cifs_oplock_break() to skip dropping a file reference. This led to busy inodes and a crash during unmount of CIFS filesystems. The fix ensures the reference is properly dropped to prevent this crash.

References

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