CVE-2026-97556: Linux kernel · smb: client: avoid leaking refcount when cifs_sb_tlink() fails
Affects Linux kernelSource GCVE Database
Not known to be exploited.
Data as of 26 Oct 2026, 12:55 UTC
Rated by Threat Radar · 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.
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
Affected software
| Product | Affected | Fixed in |
|---|---|---|
Ubuntu 26.04 LTSlinuxpkg:deb/ubuntu/linux?arch=source&distro=resoluteOther threats | Affected
| Fixed in– |
Ubuntu 26.04 LTSlinux-awspkg:deb/ubuntu/linux-aws?arch=source&distro=resoluteOther threats | Affected
| Fixed in– |
Ubuntu 26.04 LTSlinux-azurepkg:deb/ubuntu/linux-azure?arch=source&distro=resoluteOther threats | Affected
| Fixed in– |
Ubuntu 26.04 LTSlinux-azure-fdepkg:deb/ubuntu/linux-azure-fde?arch=source&distro=resoluteOther threats | Affected
| Fixed in– |
Ubuntu 26.04 LTSlinux-gcppkg:deb/ubuntu/linux-gcp?arch=source&distro=resoluteOther threats | Affected
| Fixed in– |
Ubuntu 26.04 LTSlinux-gkepkg:deb/ubuntu/linux-gke?arch=source&distro=resoluteOther threats | Affected
| Fixed in– |
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
AI-suggested
A fix for this vulnerability has been implemented in the Linux kernel. Users should update to a patched kernel version that includes this fix. Since this is a kernel-level issue, applying the official kernel updates from the Linux distribution vendor is the recommended remediation.
Description
A vulnerability in the Linux kernel's SMB client was resolved to prevent a reference count leak when the function cifs_sb_tlink() fails in multiuser setups. This leak could cause a crash due to busy inodes during unmount operations of CIFS shares. The issue occurs because cifs_oplock_break() does not properly drop a file reference on failure, leading to resource leakage and potential system instability.
References
- ubuntu.com/security/CVE-2026-97556 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2026-97556 (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)
- git.kernel.org/stable/c/dd03fd658ea59821505e0e643b6b7cbdf51c4e1d (opens in a new tab)
- git.kernel.org/stable/c/9ec991e148368e3207e98134c509a625097f7693 (opens in a new tab)
- nvd.nist.gov/vuln/detail/CVE-2026-97556 (opens in a new tab)
- git.kernel.org/stable/c/55c5f095d4df14271b238f826e1392fda7b6e60e (opens in a new tab)
- git.kernel.org/stable/c/e9c5bcc88b8337157e480c85a6d2f326bc265012 (opens in a new tab)