CVE-2026-43470: Linux kernel · nfs: return EISDIR on nfs3_proc_create if d_alias is a dir
Affects Linux kernelSource GCVE Database
Not known to be exploited · CVSS 5.5 Medium.
Data as of 26 Oct 2026, 14:05 UTC
- EPSS
- 0.1% chance of exploitation in 30 days – higher than 1% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:HExploitation evidence
Disclosed: evidence found.
CVE published 8 May 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 LTSlinux-azure-fdepkg:deb/ubuntu/linux-azure-fde?arch=source&distro=resoluteOther threats | Affected
| Fixed in– |
Ubuntu 25.10linuxpkg:deb/ubuntu/linux?arch=source&distro=questingOther threats | Affected
| Fixed in– |
Ubuntu 25.10linux-awspkg:deb/ubuntu/linux-aws?arch=source&distro=questingOther threats | Affected
| Fixed in– |
Ubuntu 25.10linux-azurepkg:deb/ubuntu/linux-azure?arch=source&distro=questingOther threats | Affected
| Fixed in– |
Ubuntu 25.10linux-azure-fdepkg:deb/ubuntu/linux-azure-fde?arch=source&distro=questingOther threats | Affected
| Fixed in– |
Ubuntu 25.10linux-gcppkg:deb/ubuntu/linux-gcp?arch=source&distro=questingOther 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 return EISDIR when a directory alias is detected during nfs3_proc_create, preventing the kernel oops. Users should apply the updated kernel versions that include this fix. Since this is a kernel-level issue, upgrading to patched kernel versions is the recommended remediation.
Description
A vulnerability in the Linux kernel's NFS implementation (CVE-2026-43470) causes a kernel oops when a directory alias is mishandled during file creation operations. Specifically, if an alias found through nfs3_do_create or related functions is a directory dentry, the kernel does not return an error but forgets the alias, leaving a negative dentry that later triggers a crash in nfs_atomic_open_v23/finish_open. This issue has been observed under concurrent directory and file creation/removal scenarios without exclusive file open flags.
References
- ubuntu.com/security/CVE-2026-43470 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2026-43470 (opens in a new tab)
- git.kernel.org/linus/410666a298c34ebd57256fde6b24c96bd23059a2 (opens in a new tab)
- git.kernel.org/stable/c/203c792cb4315360d49973ae2e57feeb6d3dcf7e (opens in a new tab)
- git.kernel.org/stable/c/410666a298c34ebd57256fde6b24c96bd23059a2 (opens in a new tab)
- git.kernel.org/stable/c/7e2963773760a664684435201960dd2fb712f1b5 (opens in a new tab)
- git.kernel.org/stable/c/9ee1770fcb2f1b48354622b926e7dc10222805f5 (opens in a new tab)