CVE-2026-89676: Linux kernel · nfsd: fix stale s2s_cp_stateids IDR entry for async COPY
Affects Linux kernelSource GCVE Database
Not known to be exploited · CVSS 9.8 Critical.
Data as of 26 Oct 2026, 14:05 UTC
- EPSS
- 0.4% chance of exploitation in 30 days – higher than 39% 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 has been implemented in the Linux kernel. Users should apply the official kernel updates corresponding to their affected versions to remediate this issue. Since this is not a cloud service, remediation depends on deploying patched kernel versions. Patch status is not explicitly stated in the provided data; users should consult their Linux distribution vendor advisories for the appropriate fixed kernel versions and update accordingly.
Description
A vulnerability in the Linux kernel's NFS server (nfsd) involving stale state ID references during asynchronous COPY operations has been resolved. The flaw caused the IDR (ID Radix tree) to point to transient memory buffers reused by subsequent requests, leading to potential use-after-free conditions. This could result in kernel memory corruption and impact confidentiality, integrity, and availability. The issue affects specific Linux kernel versions used in various Ubuntu releases.
References
- nvd.nist.gov/vuln/detail/CVE-2026-89676 (opens in a new tab)
- git.kernel.org/stable/c/14b978e8d05ce018d0afbeb6611833ef91713a02 (opens in a new tab)
- git.kernel.org/stable/c/9b4e5e9ba5ae13808b8a6d229d87c54611ba0e7a (opens in a new tab)
- git.kernel.org/stable/c/d0beaee498e11880e72826026db0e9c9890fc114 (opens in a new tab)
- ubuntu.com/security/CVE-2026-89676 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2026-89676 (opens in a new tab)
- git.kernel.org/linus/d0beaee498e11880e72826026db0e9c9890fc114 (opens in a new tab)