{"id":"CVE-2026-89662","summary":"NFSD: Prevent lock owner use-after-free during client teardown","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nNFSD: Prevent lock owner use-after-free during client teardown\n\n__destroy_client() releases a client's open owners, but a lock owner\nwhose only reference is a blocked lock (nbl) stays on\ncl_ownerstr_hashtbl.  client_has_state() does not count a bare owner,\nso DESTROY_CLIENTID can reach __destroy_client() with such owners\npresent.\n\n__destroy_client() then walks the table, calling remove_blocked_locks()\non each owner without a reference.  Freeing a blocked lock drops the\nowner reference held via flc_owner.  The per-net laundromat reaps\nblocked locks from nn-\u003eblocked_locks_lru independently of client state.\nThe two paths share blocked_locks_lock only for the list splice, not\nthe owner's lifetime.  The laundromat therefore frees the owner as\n__destroy_client() dereferences it, a NULL dereference in\nremove_blocked_locks().\n\nnfsd4_release_lockowner() holds a reference across the same call;\n__destroy_client() does not.  Hold cl_lock across the walk, taking a\nreference and unhashing each owner, then drop it before\nremove_blocked_locks() and nfs4_put_stateowner(), which take\nblocked_locks_lock and cl_lock.","modified":"2026-09-13T03:47:20.237744248Z","published":"2026-09-11T19:45:49.833Z","database_specific":{"cna_assigner":"Linux","osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/89xxx/CVE-2026-89662.json"},"references":[{"type":"WEB","url":"https://git.kernel.org/stable/c/4804c58f73a80d12df1de323bf97a164f6ee8743"},{"type":"WEB","url":"https://git.kernel.org/stable/c/5e2fa29d223a9a1e6a948e40b109d09081d1decd"},{"type":"WEB","url":"https://git.kernel.org/stable/c/8cf4ff0a7c083dd5e0067f517d63979b74b66649"},{"type":"WEB","url":"https://git.kernel.org/stable/c/a6ead6fff3a7d03e49845f048f7000a2e0d34431"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/89xxx/CVE-2026-89662.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-89662"},{"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":"68ef3bc3166468678d5e1fdd216628c35bd1186f"},{"fixed":"a6ead6fff3a7d03e49845f048f7000a2e0d34431"},{"fixed":"4804c58f73a80d12df1de323bf97a164f6ee8743"},{"fixed":"8cf4ff0a7c083dd5e0067f517d63979b74b66649"},{"fixed":"5e2fa29d223a9a1e6a948e40b109d09081d1decd"}]},{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"0"},{"last_affected":"e294c4c2d33b7307a89cdf31bec08a112d6a9297"},{"last_affected":"797bfd05d4040fbf766198b3cfcc1838002cc890"},{"last_affected":"0f44e9da465ea259b6c9f31a627f3c50a16e1679"}]},{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"4.9.91"},{"fixed":"4.10"}]},{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"4.14.31"},{"fixed":"4.15"}]},{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"4.15.14"},{"fixed":"4.16"}]}],"versions":["v4.9.90","v4.14.30","v4.15.13","v4.15.12","v4.14.29","v4.9.89","v4.9.88","v4.14.28","v4.15.11","v4.15.10","v4.14.27","v4.9.87","v4.15.9","v4.14.26","v4.15.8","v4.14.25","v4.9.86","v4.15.7","v4.14.24","v4.14","v4.14.23","v4.9.85","v4.15","v4.15.6","v4.14.22","v4.9.84","v4.15.5","v4.14.21","v4.9.83","v4.9.82","v4.14.20","v4.15.4","v4.9.81","v4.14.19","v4.15.3","v4.9.80","v4.14.18","v4.15.2","v4.15.1","v4.14.17","v4.15-rc1","v4.14.16","v4.9.79","v4.15-rc4","v4.14.15","v4.9.78","v4.15-rc9","v4.14.14","v4.9.77","v4.15-rc8","v4.15-rc7","v4.14.13","v4.9.76","v4.15-rc3","v4.15-rc2","v4.15-rc5","v4.15-rc6","v4.14.12","v4.9.75","v4.14.11","v4.9.74","v4.9.73","v4.14.10","v4.14.9","v4.9.72","v4.14.8","v4.9.71","v4.14.7","v4.9.70","v4.14.6","v4.9.69","v4.14.5","v4.9.68","v4.14.4","v4.9.67","v4.14.3","v4.9.66","v4.14.2","v4.9.65","v4.14-rc1","v4.14.1","v4.9.64","v4.14-rc7","v4.9.63","v4.9.62","v4.9.61","v4.14-rc3","v4.13","v4.14-rc8","v4.9.60","v4.14-rc4","v4.14-rc6","v4.9.59","v4.14-rc2","v4.14-rc5","v4.9.58","v4.9.57","v4.9.56","v4.9.55","v4.9.54","v4.9.53","v4.9.52","v4.9.51","v4.13-rc2","v4.9.50","v4.9.49","v4.9.48","v4.13-rc1","v4.13-rc3","v4.9.47","v4.13-rc7","v4.9.46","v4.13-rc4","v4.13-rc5","v4.13-rc6","v4.9.45","v4.9.44","v4.9.43","v4.9.42","v4.9.41","v4.9.40","v4.12-rc1","v4.9.39","v4.12","v4.9.38","v4.9.37","v4.12-rc5","v4.9.36","v4.12-rc7","v4.9.35","v4.12-rc6","v4.12-rc4","v4.9.34","v4.12-rc2","v4.9.33","v4.12-rc3","v4.9.32","v4.11","v4.9.31","v4.9.30","v4.9.29","v4.9.28","v4.9.27","v4.11-rc1","v4.9.26","v4.11-rc6","v4.9.25","v4.11-rc8","v4.9.24","v4.11-rc7","v4.11-rc3","v4.9.23","v4.11-rc5","v4.11-rc2","v4.9.22","v4.11-rc4","v4.9.21","v4.9.20","v4.9.19","v4.9.18","v4.10","v4.9.17","v4.9.16","v4.9.15","v4.9.14","v4.9.13","v4.9","v4.9.12","v4.9.11","v4.10-rc8","v4.10-rc3","v4.10-rc1","v4.10-rc7","v4.9.10","v4.10-rc6","v4.10-rc2","v4.9.9","v4.10-rc5","v4.9.8","v4.9.7","v4.9.6","v4.10-rc4","v4.9.5","v4.9.4","v4.9.3","v4.9.2","v4.9.1","v4.9-rc7","v4.9-rc6","v4.9-rc8","v4.9-rc1","v4.9-rc5","v4.9-rc3","v4.9-rc4","v4.9-rc2","v4.8","v4.8-rc8","v4.8-rc2","v4.8-rc1","v4.8-rc7","v4.8-rc6","v4.8-rc5","v4.8-rc4","v4.8-rc3","v4.7","v4.7-rc4","v4.7-rc2","v4.7-rc1","v4.7-rc7","v4.7-rc6","v4.7-rc3","v4.7-rc5","v4.6","v4.6-rc1","v4.6-rc6","v4.6-rc4","v4.6-rc7","v4.6-rc5","v4.5-rc4","v4.6-rc2","v4.6-rc3","v4.5","v4.4","v4.5-rc1","v4.5-rc6","v4.5-rc2","v4.5-rc7","v4.5-rc5","v4.5-rc3","v4.4-rc1","v4.4-rc2","v4.4-rc8","v4.4-rc3","v4.4-rc7","v4.4-rc5","v4.4-rc6","v4.4-rc4","v4.3","v4.3-rc1","v4.3-rc6","v4.3-rc4","v4.3-rc2","v4.3-rc7","v4.3-rc5","v4.3-rc3","v4.2","v4.2-rc2","v4.2-rc1","v4.2-rc8","v4.2-rc4","v4.2-rc6","v4.2-rc7","v4.0-rc5","v4.2-rc5","v4.2-rc3","v4.1-rc2","v4.1","v4.1-rc1","v4.1-rc8","v4.1-rc7","v4.1-rc6","v4.1-rc3","v4.1-rc4","v4.0","v4.1-rc5","v4.0-rc1","v4.0-rc2","v4.0-rc7","v4.0-rc3","v4.0-rc6","v4.0-rc4","v3.19","v3.19-rc7","v3.19-rc5","v3.19-rc1","v3.19-rc6","v3.19-rc4","v3.18-rc1","v3.19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