CVE-2026-64108
In the Linux kernel, the following vulnerability has been resolved: cifs: Fix busy dentry used after unmounting Since commit 340cea84f691c ("cifs: open files should not hold ref on superblock"), cifs file only holds the dentry ref_cnt, the cifs file close work(cfile->deferred) could be executed after unmounting, which will trigger a warning in generic_shutdown_super: BUG: Dentry 00000000a14a6845{i=c,n=file} still in use (1) [unmount of cifs cifs] The detailed processs is: process A process B kworker fd = open(PATH) vfs_open file->__f_path = *path // dentry->d_lockref.count = 1 cifs_open cifs_new_fileinfo cfile->dentry = dget(dentry) // dentry->d_lockref.count = 2 close(fd) __fput cifs_close queue_delayed_work(deferredclose_wq, cfile->deferred) dput(dentry) // dentry->d_lockref.count = 1 smb2_deferred_work_close _cifsFileInfo_put list_del(&cifs_file->flist) umount cleanup_mnt deactivate_super cifs_kill_sb cifs_close_all_deferred_files_sb cifs_close_all_deferred_files // cannot find cfile, skip _cifsFileInfo_put kill_anon_super
No public exploitation has been reported so far. No distribution fix is listed yet; apply vendor mitigations and monitor.
Recommended action: Track your distribution's security tracker and apply the fix as soon as it ships.
Severity metrics
CVSS 3.1 : 7.8 HIGH
Vector: AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Affected & fixed versions by distribution
Versions are the native distribution strings (backport-aware): RHEL/Debian/SUSE backport fixes, so compare with the distro version comparator (dpkg / rpm / vercmp), not the upstream version.
No affected package in the tracked watchlist yet (Debian, Ubuntu, Arch, SUSE, Red Hat...). Triage may still be pending.