{"cve":"CVE-2021-47507","nvd":{"published":"2024-05-24T15:15:11.400","modified":"2026-06-17T04:17:39.120","status":"Analyzed","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nnfsd: Fix nsfd startup race (again)\n\nCommit bd5ae9288d64 (\"nfsd: register pernet ops last, unregister first\")\nhas re-opened rpc_pipefs_event() race against nfsd_net_id registration\n(register_pernet_subsys()) which has been fixed by commit bb7ffbf29e76\n(\"nfsd: fix nsfd startup race triggering BUG_ON\").\n\nRestore the order of register_pernet_subsys() vs register_cld_notifier().\nAdd WARN_ON() to prevent a future regression.\n\nCrash info:\nUnable to handle kernel NULL pointer dereference at virtual address 0000000000000012\nCPU: 8 PID: 345 Comm: mount Not tainted 5.4.144-... #1\npc : rpc_pipefs_event+0x54/0x120 [nfsd]\nlr : rpc_pipefs_event+0x48/0x120 [nfsd]\nCall trace:\n rpc_pipefs_event+0x54/0x120 [nfsd]\n blocking_notifier_call_chain\n rpc_fill_super\n get_tree_keyed\n rpc_fs_get_tree\n vfs_get_tree\n do_mount\n ksys_mount\n __arm64_sys_mount\n el0_svc_handler\n el0_svc","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H","score":4.7},"cwes":["CWE-362"],"references":["https://git.kernel.org/stable/c/8bf902fee5893cfc2f04a698abab47629699ae9a","https://git.kernel.org/stable/c/b10252c7ae9c9d7c90552f88b544a44ee773af64","https://git.kernel.org/stable/c/c520943a00ad5015704969ad3304c956bcd49d25","https://git.kernel.org/stable/c/f5734b1714ca355703e9ea8fb61d04beff1790b9","https://git.kernel.org/stable/c/8bf902fee5893cfc2f04a698abab47629699ae9a"],"products":["linux:linux_kernel"],"source":"nvd","synced_at":"2026-10-19T21:50:30.954589733+00:00"},"epss":{"cve":"CVE-2021-47507","score":0.00187,"percentile":0.0832,"date":"2026-11-01"},"kev":null,"osv":[],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}