CVE-2026-89595: Linux kernel · fsnotify: Fix stale object mask after concurrent mark updates
Affects Linux kernelSource GCVE Database
Not known to be exploited.
Data as of 26 Oct 2026, 13:47 UTC
Rated by Threat Radar · CVSS not yet scored by NVD
- EPSS
- 0.2% chance of exploitation in 30 days – higher than 11% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Exploitation 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 in the Linux kernel. Users should update to a patched kernel version that includes the fsnotify mask recalculation fix. Since this is a kernel-level issue, applying the official kernel updates from the Linux distribution vendor is the recommended remediation. Patch status is not explicitly stated in the input data; therefore, check the vendor advisory for current remediation guidance.
Description
A vulnerability in the Linux kernel's fsnotify subsystem causes stale object masks after concurrent mark updates. This race condition can lead to missed event notifications such as FAN_MODIFY or IN_MODIFY when multiple fanotify or inotify marks on the same inode are updated concurrently. The issue affects specific Linux kernel versions and was reproducible on an unmodified v6.12.95 kernel. The flaw was addressed by ensuring recalculation of masks whenever raw mark masks change or ignore-mask updates occur, preventing stale state after concurrent updates.
References
- nvd.nist.gov/vuln/detail/CVE-2026-89595 (opens in a new tab)
- git.kernel.org/stable/c/947400af98b9e63841929d079a2c3ea0a8ba227b (opens in a new tab)
- git.kernel.org/stable/c/ac8d8b599d466a129122bded77db3d0f8b96b461 (opens in a new tab)
- git.kernel.org/stable/c/e422777fdd4746de1109575c51e65038d4c5c1be (opens in a new tab)
- ubuntu.com/security/CVE-2026-89595 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2026-89595 (opens in a new tab)
- git.kernel.org/linus/e422777fdd4746de1109575c51e65038d4c5c1be (opens in a new tab)