CVE-2026-97556: Linux kernel · smb: client: avoid leaking refcount when cifs_sb_tlink() fails
Affects Linux kernelSource CVE Database V5
Not known to be exploited · fixed in e9c5bcc88b8337157e480c85a6d2f326bc265012 : update Linux kernel when convenient.
Data as of 26 Oct 2026, 17:16 UTC
Rated Medium by Threat Radar's AI analysis · CVSS not yet scored by NVD
- EPSS
- 0.2% chance of exploitation in 30 days – higher than 10% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available – fixed in e9c5bcc88b8337157e480c85a6d2f326bc265012, dd03fd658ea59821505e0e643b6b7cbdf51c4e1d, 55c5f095d4df14271b238f826e1392fda7b6e60e +6
Exploitation evidence
Disclosed: evidence found.
CVE published 25 Sep 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by 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 26 Oct 2026.
What to do
Upgrade to a fixed release listed under Affected software.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| LinuxLinux | Affected
| Fixed in
|
| LinuxLinux | Affected
| Fixed in– |
AI-suggested
A fix is available and has been applied in Linux kernel versions 6.1.189, 5.16, 6.5, and related commits. Users should upgrade to these fixed versions to resolve the reference leak and prevent crashes. No additional mitigation is required beyond applying the official patch.
Description
A reference count leak vulnerability in the Linux kernel SMB client was fixed. The issue occurred when cifs_sb_tlink() failed in multiuser setups, causing cifs_oplock_break() to skip releasing a file reference. This led to busy inodes and a crash during unmount of CIFS filesystems. The fix ensures the reference is properly dropped on failure paths to prevent resource leaks and subsequent crashes.
References
- git.kernel.org/stable/c/55c5f095d4df14271b238f826e1392fda7b6e60e (opens in a new tab)
- git.kernel.org/stable/c/e9c5bcc88b8337157e480c85a6d2f326bc265012 (opens in a new tab)
- git.kernel.org/stable/c/9ec991e148368e3207e98134c509a625097f7693 (opens in a new tab)
- git.kernel.org/stable/c/dd03fd658ea59821505e0e643b6b7cbdf51c4e1d (opens in a new tab)
- git.kernel.org/stable/c/1d1b0f1d812a4011a57bc6c70492c34a2e46c6dd (opens in a new tab)
- git.kernel.org/stable/c/23b26f4408ac3f35a482d2e5cf6fc865d4201b71 (opens in a new tab)