CVE-2026-43470: nfs: return EISDIR on nfs3_proc_create if d_alias is a dir
In the Linux kernel, the following vulnerability has been resolved:
nfs: return EISDIR on nfs3proccreate if dalias is a dir
If we found an alias through nfs3docreate/nfsaddorobtain /dsplicealias which happens to be a dir dentry, we don't return any error, and simply forget about this alias, but the original dentry we were adding and passed as parameter remains negative.
This later causes an oops on nfsatomicopenv23/finishopen since we supply a negative dentry to dodentryopen.
This has been observed running lustre-racer, where dirs and files are created/removed concurrently with the same name and OEXCL is not used to open files (frequent file redirection).
While dsplicealias typically returns a directory alias or NULL, we explicitly check disdir() to ensure that we don't attempt to perform file operations (like finishopen) on a directory inode, which triggers the observed oops.
Affected Software
Remediation
Event History
Frequently Asked Questions
What is the severity of CVE-2026-43470?
CVE-2026-43470 is considered a moderate severity vulnerability due to its impact on file creation operations in the NFS protocol.
How do I fix CVE-2026-43470?
To fix CVE-2026-43470, update your Linux kernel to the latest patched version that addresses this vulnerability.
Which systems are affected by CVE-2026-43470?
CVE-2026-43470 affects the Linux kernel, particularly systems utilizing the NFS protocol for file operations.
What is the nature of the vulnerability in CVE-2026-43470?
CVE-2026-43470 involves improper handling of directory entries in the NFS protocol, leading to incorrect EISDIR errors.
When was CVE-2026-43470 disclosed?
CVE-2026-43470 was disclosed in 2026 as part of ongoing security enhancements to the Linux kernel.