CVE-2026-89707: Linux kernel · nfsd: release path refs on follow_down() error
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 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 properly releases path references on all error returns in nfsd_cross_mnt(). Users should apply the official Linux kernel patches that address this issue. Since this is a kernel-level vulnerability, updating to a patched kernel version is the recommended remediation. Patch status is not explicitly confirmed in the provided data; therefore, check the vendor advisory for current remediation guidance.
Description
A vulnerability in the Linux kernel's NFS daemon (nfsd) causes a reference leak on error paths in the follow_down() function. This leak inflates mount and dentry reference counts, potentially blocking unmount operations and pinning dentries against cleanup. The issue affects certain Linux kernel versions and can be triggered by any authenticated NFS client. The vulnerability has a medium severity with an impact on availability but no confidentiality or integrity loss.
References
- nvd.nist.gov/vuln/detail/CVE-2026-89707 (opens in a new tab)
- git.kernel.org/stable/c/194316df81263519156ebe714c4a286bee00e5be (opens in a new tab)
- git.kernel.org/stable/c/2bc4343308d85ee4e0dd3877b384306c96f114c2 (opens in a new tab)
- git.kernel.org/stable/c/467d56fd3ff57447a790c6dc3ede2d02a947d224 (opens in a new tab)
- git.kernel.org/stable/c/6cba08dc1922140d260cfeb30bbda4ee1bf869d8 (opens in a new tab)
- ubuntu.com/security/CVE-2026-89707 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2026-89707 (opens in a new tab)
- git.kernel.org/linus/6cba08dc1922140d260cfeb30bbda4ee1bf869d8 (opens in a new tab)