CVE-2026-89767: Linux kernel · ovl: fix double end_creating() on the casefold-mismatch path
Affects Linux kernelSource GCVE Database
Not known to be exploited · CVSS 7.8 High.
Data as of 26 Oct 2026, 14:05 UTC
- EPSS
- 0.1% chance of exploitation in 30 days – higher than 6% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
CVSS:3.1/AV:L/AC:L/PR:L/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
No explicit patch links or vendor advisory are provided in the input data. Until patched, avoid using overlay filesystem configurations that enable casefolding on the work directory or untrusted user operations that could trigger this condition.
Description
A vulnerability in the Linux kernel overlay filesystem (ovl) causes a double call to end_creating() on the casefold-mismatch path in ovl_create_real(). This results in unlocking a lock twice and dropping a reference twice, which can wedge subsequent directory creation operations under the affected parent directory. The flaw is reachable by unprivileged users and affects specific Linux kernel versions.
References
- nvd.nist.gov/vuln/detail/CVE-2026-89767 (opens in a new tab)
- git.kernel.org/stable/c/077ab8985ee278c3d8618182d335b0f0cd919e16 (opens in a new tab)
- git.kernel.org/stable/c/2fa220bc0f84597cb6de665e5b5021c5901ddf00 (opens in a new tab)
- git.kernel.org/stable/c/b1aa8ab78a8e87aee9e306971465408e059f839a (opens in a new tab)
- ubuntu.com/security/CVE-2026-89767 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2026-89767 (opens in a new tab)
- git.kernel.org/linus/077ab8985ee278c3d8618182d335b0f0cd919e16 (opens in a new tab)