{"id":"CVE-2026-64108","summary":"cifs: Fix busy dentry used after unmounting","details":"In the Linux kernel, the following vulnerability has been resolved:\n\ncifs: Fix busy dentry used after unmounting\n\nSince commit 340cea84f691c (\"cifs: open files should not hold ref on\nsuperblock\"), cifs file only holds the dentry ref_cnt, the cifs file\nclose work(cfile-\u003edeferred) could be executed after unmounting, which\nwill trigger a warning in generic_shutdown_super:\n BUG: Dentry 00000000a14a6845{i=c,n=file}  still in use (1) [unmount of\n cifs cifs]\n\nThe detailed processs is:\n   process A           process B           kworker\n fd = open(PATH)\n  vfs_open\n   file-\u003e__f_path = *path // dentry-\u003ed_lockref.count = 1\n   cifs_open\n    cifs_new_fileinfo\n     cfile-\u003edentry = dget(dentry) // dentry-\u003ed_lockref.count = 2\n close(fd)\n  __fput\n  cifs_close\n   queue_delayed_work(deferredclose_wq, cfile-\u003edeferred)\n  dput(dentry) // dentry-\u003ed_lockref.count = 1\n\t\t\t                 smb2_deferred_work_close\n\t\t\t\t\t  _cifsFileInfo_put\n\t\t\t\t\t   list_del(&cifs_file-\u003eflist)\n                    umount\n\t\t     cleanup_mnt\n\t\t      deactivate_super\n\t\t       cifs_kill_sb\n\t\t        cifs_close_all_deferred_files_sb\n\t\t\t cifs_close_all_deferred_files\n\t\t\t  // cannot find cfile, skip _cifsFileInfo_put\n\t\t\tkill_anon_super\n\t\t\t generic_shutdown_super\n\t\t\t  shrink_dcache_for_umount\n\t\t\t   umount_check\n\t\t\t    WARN ! // dentry-\u003ed_lockref.count = 1\n\t\t\t\t\t   cifsFileInfo_put_final\n\t\t\t\t\t    dput(cifs_file-\u003edentry)\n\t\t                            // dentry-\u003ed_lockref.count = 0\n\nFix it by flushing 'deferredclose_wq' before calling kill_anon_super.\n\nFetch a reproducer in https://bugzilla.kernel.org/show_bug.cgi?id=221548.","modified":"2026-10-08T02:51:29.809013371Z","published":"2026-07-19T15:40:10.784Z","database_specific":{"cna_assigner":"Linux","osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/64xxx/CVE-2026-64108.json"},"references":[{"type":"WEB","url":"https://git.kernel.org/stable/c/5e7d9d0805e58fa3760894e73115b7a74024fd07"},{"type":"WEB","url":"https://git.kernel.org/stable/c/bdc349a87f1fb02c18c4071858a06542bfea783d"},{"type":"WEB","url":"https://git.kernel.org/stable/c/c68337442f03953237a94577beb468ab2662a851"},{"type":"WEB","url":"https://git.kernel.org/stable/c/c7364cea52531534676b9f7dbc0a477c11f4c050"},{"type":"WEB","url":"https://git.kernel.org/stable/c/e1ffa6cf662383f95816eed1b623429d82675e75"},{"type":"WEB","url":"https://git.kernel.org/stable/c/f2deaa2f409a4598eaa10f2a93a676c0632af248"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/64xxx/CVE-2026-64108.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-64108"},{"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":"708c276f516d27beaded7f372ac8111cee43926c"},{"fixed":"c7364cea52531534676b9f7dbc0a477c11f4c050"}]},{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"0629a1a187e424373364d681b42b101894bdb548"},{"fixed":"bdc349a87f1fb02c18c4071858a06542bfea783d"}]},{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"0e4b8faaaebe3137bec5723ef2b3cb0437fb38fd"},{"fixed":"f2deaa2f409a4598eaa10f2a93a676c0632af248"}]},{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"f655467a9973f964b267871e5fef533ad5014494"},{"fixed":"5e7d9d0805e58fa3760894e73115b7a74024fd07"}]},{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"340cea84f691c5206561bb2e0147158fe02070be"},{"fixed":"e1ffa6cf662383f95816eed1b623429d82675e75"},{"fixed":"c68337442f03953237a94577beb468ab2662a851"}]},{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"6.1.167"},{"fixed":"6.1.175"}]},{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"6.6.130"},{"fixed":"6.6.142"}]},{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"6.12.78"},{"fixed":"6.12.92"}]},{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"6.18.20"},{"fixed":"6.18.34"}]},{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"6.19.10"},{"fixed":"6.20"}]},{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"30afc6ea72cc6cf7c8d579e79b64232801c38d08"}]}],"versions":["v6.1.174","v6.1.173","v6.1.172","v6.1.171","v6.1.170","v6.1.169","v6.1.168","v6.1.167","v6.6.141","v6.6.140","v6.6.139","v6.6.138","v6.6.137","v6.6.136","v6.6.135","v6.6.134","v6.6.133","v6.6.132","v6.6.131","v6.6.130","v6.12.91","v6.12.90","v6.12.89","v6.12.88","v6.12.87","v6.12.86","v6.12.85","v6.12.84","v6.12.83","v6.12.82","v6.12.81","v6.12.80","v6.12.79","v6.12.78","v6.18.33","v6.18.32","v6.18.31","v6.18.30","v6.18.29","v6.18.28","v6.18.27","v6.18.26","v6.18.25","v6.18.24","v6.18.23","v6.18.22","v6.18.21","v6.18.20","v6.19.14","v6.19.13","v6.19.12","v6.19.11","v6.19.10"],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-64108.json"}},{"package":{"name":"Kernel","ecosystem":"Linux"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"6.1.175"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.2.0"},{"fixed":"6.6.142"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.7.0"},{"fixed":"6.12.92"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.13.0"},{"fixed":"6.18.34"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.19.0"},{"fixed":"7.0.11"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-64108.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H"}]}