CVE-2026-80926: Linux kernel · ksmbd: fix use-after-free in oplock break notification
Affects Linux kernelSource GCVE Database
Not known to be exploited · CVSS 9.8 Critical.
Data as of 26 Oct 2026, 13:47 UTC
- EPSS
- 0.4% chance of exploitation in 30 days – higher than 38% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:HExploitation evidence
Disclosed: evidence found.
CVE published 11 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 is available and should be applied by updating to patched Linux kernel versions. The patch ensures proper locking and reference counting to prevent use-after-free conditions in ksmbd oplock break notifications. Users should upgrade to kernel versions that include this fix. No additional mitigations are indicated by the vendor advisory.
Description
A critical use-after-free vulnerability in the Linux kernel's ksmbd component related to oplock break notifications has been resolved. The flaw involves unsafe dereferencing of a connection pointer after it may have been freed during concurrent operations. This vulnerability affects multiple specific Linux kernel versions and allows an authenticated client holding a durable batch oplock to potentially exploit the use-after-free condition. The fix involves proper locking and reference management to prevent resurrection of freed connections during oplock break notifications.
References
- nvd.nist.gov/vuln/detail/CVE-2026-80926 (opens in a new tab)
- git.kernel.org/stable/c/0e753899627b5e28a9fea8bca98262a6f65a2452 (opens in a new tab)
- git.kernel.org/stable/c/8cc98db4fc590e6c7d9db6529320982ee16c5d1d (opens in a new tab)
- git.kernel.org/stable/c/c8279ae8df68cce9cd3b785e85f7a86c80a46e78 (opens in a new tab)
- ubuntu.com/security/CVE-2026-80926 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2026-80926 (opens in a new tab)
- git.kernel.org/linus/0e753899627b5e28a9fea8bca98262a6f65a2452 (opens in a new tab)
- git.kernel.org/stable/c/5de0527f782430b1109a447646e32033ad018a6a (opens in a new tab)
- git.kernel.org/stable/c/892f643b141aee3f7aa7c0fc61ddcb55c59f1996 (opens in a new tab)