CVE-2026-89683

In the Linux kernel, the following vulnerability has been resolved:

nfsd: fix dentry ref leak on V4ROOT export filehandle lookup

nfsd_set_fh_dentry() leaks the dentry reference from exportfs_decode_fh_raw() when the NFS3_FHSIZE or NFS_FHSIZE switch cases detect NFSEXP_V4ROOT and goto out. The out: label calls exp_put() but never dput(dentry), and fhp->fh_dentry was never assigned so fh_put() cannot compensate.

A crafted NFSv3 filehandle targeting a V4ROOT export's fsid triggers the leak on every request.