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.
References 4
https://git.kernel.org/stable/c/11db8df188b34bdb8c6a3a0bf438e5fc8cd75aca
416baaa9-dc9f-4396-8d5f-8c081fb06d67
https://git.kernel.org/stable/c/6247023fbbec1325029f2d5f2a7cdc0f9f9ea15a
416baaa9-dc9f-4396-8d5f-8c081fb06d67
https://git.kernel.org/stable/c/c1ae0f973bcba5730871e35976a0ab6878fdac34
416baaa9-dc9f-4396-8d5f-8c081fb06d67
https://git.kernel.org/stable/c/d493cf57f4c4dae5396cd6ad41e5c209d0615a81
416baaa9-dc9f-4396-8d5f-8c081fb06d67