{"cve":"CVE-2026-64108","nvd":{"published":"2026-07-19T16:17:52.100","modified":"2026-08-12T15:14:14.520","status":"Analyzed","description":"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->deferred) 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->__f_path = *path // dentry->d_lockref.count = 1\n   cifs_open\n    cifs_new_fileinfo\n     cfile->dentry = dget(dentry) // dentry->d_lockref.count = 2\n close(fd)\n  __fput\n  cifs_close\n   queue_delayed_work(deferredclose_wq, cfile->deferred)\n  dput(dentry) // dentry->d_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->flist)\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->d_lockref.count = 1\n\t\t\t\t\t   cifsFileInfo_put_final\n\t\t\t\t\t    dput(cifs_file->dentry)\n\t\t                            // dentry->d_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.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","score":7.8},"cwes":[],"references":["https://git.kernel.org/stable/c/5e7d9d0805e58fa3760894e73115b7a74024fd07","https://git.kernel.org/stable/c/bdc349a87f1fb02c18c4071858a06542bfea783d","https://git.kernel.org/stable/c/c68337442f03953237a94577beb468ab2662a851","https://git.kernel.org/stable/c/c7364cea52531534676b9f7dbc0a477c11f4c050","https://git.kernel.org/stable/c/e1ffa6cf662383f95816eed1b623429d82675e75"],"products":["linux:linux_kernel"],"source":"nvd","synced_at":"2026-10-19T22:45:36.895656543+00:00"},"epss":{"cve":"CVE-2026-64108","score":0.00129,"percentile":0.0254,"date":"2026-10-31"},"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."]}