CVE-2026-89672: Linux kernel · nfsd: gate nfs2 setacl by argp->mask
Affects Linux kernelSource GCVE Database
Not known to be exploited · CVSS 9.1 Critical.
Data as of 26 Oct 2026, 14:05 UTC
- EPSS
- 0.5% chance of exploitation in 30 days – higher than 44% 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:NExploitation 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 by gating set_posix_acl() calls on the corresponding mask bits and ensuring no ACLs are removed when no mask bits are set. Users should apply the official kernel updates that include this fix. Since this is a kernel-level vulnerability, upgrading to a patched kernel version is the recommended remediation.
Description
A vulnerability in the Linux kernel's NFS server (nfsd) affects the handling of NFSACL v2 SETACL requests. The flaw allows improper handling of ACL mask bits, causing unintended removal of directory default ACLs when certain mask bits are omitted or zeroed. This issue was fixed by gating calls to set_posix_acl() based on the mask bits to prevent accidental ACL deletion.
References
- nvd.nist.gov/vuln/detail/CVE-2026-89672 (opens in a new tab)
- git.kernel.org/stable/c/37eea38e7898538f0ec5f1eb8b18d8646e4be41c (opens in a new tab)
- git.kernel.org/stable/c/a3a7e20ed66d3f04d37883c398da8a113b430769 (opens in a new tab)
- git.kernel.org/stable/c/e41d173d9dc735cecb15ab7aa63ecab09338f81b (opens in a new tab)
- git.kernel.org/stable/c/f951b22dbeec46f2e0fba81cb80d1b0c686b61eb (opens in a new tab)
- ubuntu.com/security/CVE-2026-89672 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2026-89672 (opens in a new tab)
- git.kernel.org/linus/a3a7e20ed66d3f04d37883c398da8a113b430769 (opens in a new tab)