CVE-2026-43470 nfs: return EISDIR on nfs3_proc_create if d_alias is a dir
A race condition in the Linux kernel NFS client can cause a null pointer dereference and system crash when creating files concurrently with directories.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-43470?
CVE-2026-43470 is a medium-severity vulnerability in Linux kernel, published on 8 May 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
In the Linux kernel, the following vulnerability has been resolved:
nfs: return EISDIR on nfs3_proc_create if d_alias is a dir
If we found an alias through nfs3_do_create/nfs_add_or_obtain /d_splice_alias 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 nfs_atomic_open_v23/finish_open since we supply a negative dentry to do_dentry_open.
This has been observed running lustre-racer, where dirs and files are created/removed concurrently with the same name and O_EXCL is not used to open files (frequent file redirection).
While d_splice_alias typically returns a directory alias or NULL, we explicitly check d_is_dir() to ensure that we don't attempt to perform file operations (like finish_open) on a directory inode, which triggers the observed oops.
Which versions are affected by CVE-2026-43470?
It affects 1 product.
Products include Linux kernel.
How do I fix CVE-2026-43470?
Apply the vendor's patch.
Is CVE-2026-43470 being exploited?
There is no known exploitation of CVE-2026-43470 in the wild and no public exploit code.
Other vulnerabilities in Linux kernel
Sources
Also known as BELL-CVE-2026-43470, DEBIAN-CVE-2026-43470, GHSA-jprv-4f6g-4wvm, UBUNTU-CVE-2026-43470.