CVE-2026-89685: Linux kernel · nfsd: fix clock domain mismatch in clients_still_reclaiming()
Affects Linux kernelSource GCVE Database
Not known to be exploited · CVSS 7.5 High.
Data as of 26 Oct 2026, 14:05 UTC
- EPSS
- 0.4% chance of exploitation in 30 days – higher than 38% 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 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 has been implemented in the Linux kernel to address this issue by correcting the clock domain mismatch. Users should apply the official kernel updates that include this patch to resolve the vulnerability.
Description
A vulnerability in the Linux kernel's NFS server (nfsd) was fixed that involved a clock domain mismatch in the clients_still_reclaiming() function. The function incorrectly compared a deadline computed from CLOCK_REALTIME with a timestamp from CLOCK_BOOTTIME, causing the comparison to always fail. This flaw allowed any client to indefinitely hold the server in grace by sending CLAIM_PREVIOUS OPEN requests, blocking other clients' non-reclaim operations.
References
- nvd.nist.gov/vuln/detail/CVE-2026-89685 (opens in a new tab)
- git.kernel.org/stable/c/09ea3eb9a518565f5bca386e81b993ed8825f5e8 (opens in a new tab)
- git.kernel.org/stable/c/9843649196221152b6e5d138a3ce859bdaae1d96 (opens in a new tab)
- git.kernel.org/stable/c/f9cec313efb2fd18d962aad738a4892bce806016 (opens in a new tab)
- ubuntu.com/security/CVE-2026-89685 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2026-89685 (opens in a new tab)
- git.kernel.org/linus/09ea3eb9a518565f5bca386e81b993ed8825f5e8 (opens in a new tab)