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CVE-2025-40212
CRITICAL · CVSS 9.8
EPSS exploitation probability: 0%
Published 2025-11-24T13:16:02.813 · Last modified 2026-07-30T06:24:18.133

Summary

In the Linux kernel, the following vulnerability has been resolved: nfsd: fix refcount leak in nfsd_set_fh_dentry() nfsd exports a "pseudo root filesystem" which is used by NFSv4 to find the various exported filesystems using LOOKUP requests from a known root filehandle. NFSv3 uses the MOUNT protocol to find those exported filesystems and so is not given access to the pseudo root filesystem. If a v3 (or v2) client uses a filehandle from that filesystem, nfsd_set_fh_dentry() will report an error, but still stores the export in "struct svc_fh" even though it also drops the reference (exp_put()). This means that when fh_put() is called an extra reference will be dropped which can lead to use-after-free and possible denial of service. Normal NFS usage will not provide a pseudo-root fileha

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References

This product uses data from the NVD API but is not endorsed or certified by the NVD. Informational only; not professional security advice.