CVE-2026-90234: Linux kernel · NFS: Return a delegation the client fails to record
Affects Linux kernelSource GCVE Database
Not known to be exploited · CVSS 7.5 High.
Data as of 26 Oct 2026, 13:47 UTC
- EPSS
- 0.6% chance of exploitation in 30 days – higher than 49% 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:N/I:N/A:HExploitation evidence
Disclosed: evidence found.
CVE published 17 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 has been implemented in the Linux kernel to address this issue by ensuring that delegations are properly returned during error flows. Users should update to a patched linux-aws kernel version that includes this fix. Since this is a kernel-level vulnerability, applying the official kernel update is the recommended remediation. No alternative mitigations are specified.
Description
A vulnerability in the Linux kernel's NFS implementation causes the client to fail to properly record delegation revocation. When the NFS server grants a delegation, certain error flows in the client do not send the required DELEGRETURN message, leaving the server believing the client still holds the delegation. This leads to the client responding with errors to delegation recalls and causes the client's state manager to loop indefinitely. The issue affects specific linux-aws kernel versions and has a CVSS score of 7.5 with medium severity.
References
- nvd.nist.gov/vuln/detail/CVE-2026-90234 (opens in a new tab)
- git.kernel.org/stable/c/220af23d863995091f0edeb1e6aa0945b3db8b37 (opens in a new tab)
- git.kernel.org/stable/c/92533e49fe3c455088657b862cf3562260c0ce25 (opens in a new tab)
- ubuntu.com/security/CVE-2026-90234 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2026-90234 (opens in a new tab)
- git.kernel.org/linus/220af23d863995091f0edeb1e6aa0945b3db8b37 (opens in a new tab)