CVE-2026-89674: Linux kernel · nfsd: fix XDR length calculation in nfsd4_ff_encode_layoutget
Affects Linux kernelSource GCVE Database
Not known to be exploited · CVSS 9.8 Critical.
Data as of 26 Oct 2026, 17:16 UTC
- EPSS
- 0.5% chance of exploitation in 30 days – higher than 43% 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 is available that corrects the XDR buffer size calculation in the nfsd4_ff_encode_layoutget function. Users should apply the updated Linux kernel versions that include this patch. Since this is a kernel vulnerability, upgrading to patched kernel versions is the recommended remediation.
Description
A vulnerability in the Linux kernel's nfsd component related to incorrect XDR buffer size calculation in the nfsd4_ff_encode_layoutget function can cause out-of-bounds writes or leak uninitialized kernel memory to clients. This occurs due to multiple errors in length calculations for file handle, uid, gid, and other fields. The issue is fixed by explicitly correcting length calculations and using proper alignment functions.
References
- nvd.nist.gov/vuln/detail/CVE-2026-89674 (opens in a new tab)
- git.kernel.org/stable/c/0380129b1373c437eb35401a174671c8888f4b80 (opens in a new tab)
- git.kernel.org/stable/c/c81cef6a805dec266c10fc4f83c93d6fcf1a2b43 (opens in a new tab)
- git.kernel.org/stable/c/e7d9d23ecd9172f05b09bb678ff22db8e361c428 (opens in a new tab)
- git.kernel.org/stable/c/f9868174af49d207fbaf0c5e055d088a983684af (opens in a new tab)
- ubuntu.com/security/CVE-2026-89674 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2026-89674 (opens in a new tab)
- git.kernel.org/linus/f9868174af49d207fbaf0c5e055d088a983684af (opens in a new tab)