{"id":"CVE-2025-40212","summary":"nfsd: fix refcount leak in nfsd_set_fh_dentry()","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nnfsd: fix refcount leak in nfsd_set_fh_dentry()\n\nnfsd exports a \"pseudo root filesystem\" which is used by NFSv4 to find\nthe various exported filesystems using LOOKUP requests from a known root\nfilehandle.  NFSv3 uses the MOUNT protocol to find those exported\nfilesystems and so is not given access to the pseudo root filesystem.\n\nIf a v3 (or v2) client uses a filehandle from that filesystem,\nnfsd_set_fh_dentry() will report an error, but still stores the export\nin \"struct svc_fh\" even though it also drops the reference (exp_put()).\nThis means that when fh_put() is called an extra reference will be dropped\nwhich can lead to use-after-free and possible denial of service.\n\nNormal NFS usage will not provide a pseudo-root filehandle to a v3\nclient.  This bug can only be triggered by the client synthesising an\nincorrect filehandle.\n\nTo fix this we move the assignments to the svc_fh later, after all\npossible error cases have been detected.","modified":"2026-03-20T12:43:13.781711Z","published":"2025-11-24T13:04:20.888Z","related":["SUSE-SU-2026:20148-1","SUSE-SU-2026:20149-1","SUSE-SU-2026:20163-1","SUSE-SU-2026:20164-1","SUSE-SU-2026:20165-1","SUSE-SU-2026:20168-1","SUSE-SU-2026:20169-1","SUSE-SU-2026:20171-1","SUSE-SU-2026:20202-1","SUSE-SU-2026:20207-1","SUSE-SU-2026:20220-1","SUSE-SU-2026:20228-1","openSUSE-SU-2026:20145-1"],"database_specific":{"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2025/40xxx/CVE-2025-40212.json","cna_assigner":"Linux"},"references":[{"type":"WEB","url":"https://git.kernel.org/stable/c/8a7348a9ed70bda1c1f51d3f1815bcbdf9f3b38c"},{"type":"WEB","url":"https://git.kernel.org/stable/c/b6bc86ce3944b10b9fc181fc00c1a520a20ed965"},{"type":"WEB","url":"https://git.kernel.org/stable/c/c83d7365cec5eb5ebeeee2a72e29b4ca58a7e4c2"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2025/40xxx/CVE-2025-40212.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2025-40212"},{"type":"PACKAGE","url":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"ef7f6c4904d03ccd7478e1ac20ed75f79c4ac444"},{"fixed":"b6bc86ce3944b10b9fc181fc00c1a520a20ed965"},{"fixed":"c83d7365cec5eb5ebeeee2a72e29b4ca58a7e4c2"},{"fixed":"8a7348a9ed70bda1c1f51d3f1815bcbdf9f3b38c"}]}],"database_specific":{"source":"https://storage.googleapis.com/osv-test-cve-osv-conversion/osv-output/CVE-2025-40212.json"}},{"package":{"name":"Kernel","ecosystem":"Linux"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"6.12.0"},{"fixed":"6.12.59"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.13.0"},{"fixed":"6.17.9"}]}],"database_specific":{"source":"https://storage.googleapis.com/osv-test-cve-osv-conversion/osv-output/CVE-2025-40212.json"}}],"schema_version":"1.7.5"}