{"id":"CVE-2026-90039","revision":"48654ae648e347ecad92c6b36e58be79","records":[{"revision":"48654ae648e347ecad92c6b36e58be79","observedAt":"2026-10-23T15:48:27.903+00:00","statement":{"source":"cve-program","id":"CVE-2026-90039","aliases":[],"title":"NFSD: Guard admin state-revocation walks with NFSD_NET_UP","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nNFSD: Guard admin state-revocation walks with NFSD_NET_UP\n\nWriting to /proc/fs/nfsd/unlock_filesystem, or sending the\nNFSD_CMD_UNLOCK_FILESYSTEM or NFSD_CMD_UNLOCK_EXPORT netlink command,\nwalks the NFSv4 client hash tables to revoke open state and cancel\nasync COPY operations.  All three handlers gate that walk on\nnn->nfsd_serv, but a listener added via portlist or netlink\nlistener_set sets nn->nfsd_serv before any nfsd thread starts.\nnfsd_startup_net() has not yet allocated nn->conf_id_hashtbl, so the\nwalkers dereference a NULL table.  A local administrator with\nCAP_SYS_ADMIN can crash the kernel this way without ever starting the\nserver.\n\nnn->nfsd_serv is set when the service is created, which precedes\ntable allocation.  NFSD_NET_UP instead brackets the window where the\ntables are live: set at the end of nfsd_startup_net() and cleared in\nnfsd_shutdown_net() after they are freed, both under nfsd_mutex.\nGating the three unlock paths on NFSD_NET_UP fixes the startup-time\nNULL dereference while preserving the earlier post-shutdown\nuse-after-free fix.","state":0,"publishedAt":"2026-09-16T10:33:38.091+00:00","modifiedAt":"2026-10-19T08:56:56.714+00:00","affected":[{"ecosystem":"Vendor product","name":"Linux","ranges":[],"versions":[],"rawVersionEvidence":"{\n                    \"product\": \"Linux\",\n                    \"vendor\": \"Linux\",\n                    \"defaultStatus\": \"unaffected\",\n                    \"repo\": \"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\n                    \"programFiles\": [\n                        \"fs/nfsd/nfs4proc.c\",\n                        \"fs/nfsd/nfs4state.c\",\n                        \"fs/nfsd/nfsctl.c\"\n                    ],\n                    \"versions\": [\n                        {\n                            \"version\": \"1ac3629bf012592cb0320e52a1cceb319a05ad17\",\n                            \"lessThan\": \"73bf459d696ecf207a9037bf9bb70c51a459469e\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"1ac3629bf012592cb0320e52a1cceb319a05ad17\",\n                            \"lessThan\": \"104a51265042b4424085741c963cb858ac29ec0b\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"1ac3629bf012592cb0320e52a1cceb319a05ad17\",\n                            \"lessThan\": \"0146467a2fce845cb6629979c3e9c58dd3d3a6a3\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"1ac3629bf012592cb0320e52a1cceb319a05ad17\",\n                            \"lessThan\": \"2f3e6638aebc0ab8afb8b4e9816ea9a1cad85378\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        }\n                    ]\n                }"},{"ecosystem":"Vendor product","name":"Linux","ranges":[],"versions":[],"rawVersionEvidence":"{\n                    \"product\": \"Linux\",\n                    \"vendor\": \"Linux\",\n                    \"defaultStatus\": \"affected\",\n                    \"repo\": \"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\n                    \"programFiles\": [\n                        \"fs/nfsd/nfs4proc.c\",\n                        \"fs/nfsd/nfs4state.c\",\n                        \"fs/nfsd/nfsctl.c\"\n                    ],\n                    \"versions\": [\n                        {\n                            \"version\": \"6.9\",\n                            \"status\": \"affected\"\n                        },\n                        {\n                            \"version\": \"0\",\n                            \"lessThan\": \"6.9\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"6.12.111\",\n                            \"lessThanOrEqual\": \"6.12.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"6.18.51\",\n                            \"lessThanOrEqual\": \"6.18.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"7.2.5\",\n                            \"lessThanOrEqual\": \"7.2.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"7.3\",\n                            \"lessThanOrEqual\": \"*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"original_commit_for_fix\"\n                        }\n                    ]\n                }"}],"metrics":[],"references":["https://git.kernel.org/stable/c/73bf459d696ecf207a9037bf9bb70c51a459469e","https://git.kernel.org/stable/c/104a51265042b4424085741c963cb858ac29ec0b","https://git.kernel.org/stable/c/0146467a2fce845cb6629979c3e9c58dd3d3a6a3","https://git.kernel.org/stable/c/2f3e6638aebc0ab8afb8b4e9816ea9a1cad85378"],"sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-90039","license":"CVE Program Terms of Use","key":"cve-program:CVE-2026-90039","identifiers":["CVE-2026-90039"]},"retained":false,"historicalAffected":[]}],"coverage":[]}