cbcvebase.
CVE-2025-40105
published 2025-10-30

CVE-2025-40105: In the Linux kernel, the following vulnerability has been resolved: vfs: Don't leak disconnected dentries on umount When user calls open_by_handle_at() on some…

PriorityP422high7.8
EPSS
0.21%
11.7th percentile
In the Linux kernel, the following vulnerability has been resolved: vfs: Don't leak disconnected dentries on umount When user calls open_by_handle_at() on some inode that is not cached, we will create disconnected dentry for it. If such dentry is a directory, exportfs_decode_fh_raw() will then try to connect this dentry to the dentry tree through reconnect_path(). It may happen for various reasons (such as corrupted fs or race with rename) that the call to lookup_one_unlocked() in reconnect_one() will fail to find the dentry we are trying to reconnect and instead create a new dentry under the parent. Now this dentry will not be marked as disconnected although the parent still may well be disconnected (at least in case this inconsistency happened because the fs is corrupted and .. doesn't point to the real parent directory). This creates inconsistency in disconnected flags but AFAICS it was mostly harmless. At least until commit f1ee616214cb ("VFS: don't keep disconnected dentries on d_anon") which removed adding of most disconnected dentries to sb->s_anon list. Thus after this commit cleanup of disconnected dentries implicitely relies on the fact that dput() will immediately reclaim such dentries. However when some leaf dentry isn't marked as disconnected, as in the scenario described above, the reclaim doesn't happen and the dentries are "leaked". Memory reclaim can eventually reclaim them but otherwise they stay in memory and if umount comes first, we hit infamous "Busy inodes after unmount" bug. Make sure all dentries created under a disconnected parent are marked as disconnected as well.

Affected

33 ranges· showing 25
VendorProductVersion rangeFixed in
debianlinux< linux 6.1.158-1 (bookworm)linux 6.1.158-1 (bookworm)
debianlinux-6.1< linux 6.1.158-1 (bookworm)linux 6.1.158-1 (bookworm)
linuxlinux
linuxlinux>= f1ee616214cb22410e939d963bbb2349c2570f02 < b5abafd0aa8d7bcb935c8f91e4cfc2f2820759e4b5abafd0aa8d7bcb935c8f91e4cfc2f2820759e4
linuxlinux>= f1ee616214cb22410e939d963bbb2349c2570f02 < 20863bb7fbb016379f8227122edfabc5c799bc7920863bb7fbb016379f8227122edfabc5c799bc79
linuxlinux>= f1ee616214cb22410e939d963bbb2349c2570f02 < 8004d4b8cbf1bd68a23c160d57287e177c82cc698004d4b8cbf1bd68a23c160d57287e177c82cc69
linuxlinux>= f1ee616214cb22410e939d963bbb2349c2570f02 < 7e0c8aaf4e28918abded547a5147c7d52c4af7d27e0c8aaf4e28918abded547a5147c7d52c4af7d2
linuxlinux>= f1ee616214cb22410e939d963bbb2349c2570f02 < cebfbf40056a4d858b2a3ca59a69936d599bd209cebfbf40056a4d858b2a3ca59a69936d599bd209
linuxlinux>= f1ee616214cb22410e939d963bbb2349c2570f02 < 620f3b0ede9c5cb4976cd0457d0b04ad551e5d6b620f3b0ede9c5cb4976cd0457d0b04ad551e5d6b
linuxlinux>= f1ee616214cb22410e939d963bbb2349c2570f02 < eadc49999fa994d6fbd70c332bd5d5051cc42261eadc49999fa994d6fbd70c332bd5d5051cc42261
linuxlinux>= f1ee616214cb22410e939d963bbb2349c2570f02 < 56094ad3eaa21e6621396cc33811d8f72847a83456094ad3eaa21e6621396cc33811d8f72847a834
linuxlinux_kernel>= 0 < 5.10.247-15.10.247-1
linuxlinux_kernel>= 0 < 6.1.158-16.1.158-1
linuxlinux_kernel>= 0 < 6.12.57-16.12.57-1
linuxlinux_kernel>= 0 < 6.17.6-16.17.6-1
linuxlinux_kernel>= 0 < 5.15.0-170.1805.15.0-170.180
linuxlinux_kernel>= 0 < 6.8.0-106.1066.8.0-106.106
linuxlinux_kernel>= 0 < 6.17.0-14.146.17.0-14.14
linuxlinux_kernel>= 4.16.0 < 5.4.3015.4.301
linuxlinux_kernel>= 5.11.0 < 5.15.1965.15.196
linuxlinux_kernel>= 5.16.0 < 6.1.1586.1.158
linuxlinux_kernel>= 5.5.0 < 5.10.2465.10.246
linuxlinux_kernel>= 6.13.0 < 6.17.56.17.5
linuxlinux_kernel>= 6.2.0 < 6.6.1146.6.114
linuxlinux_kernel>= 6.7.0 < 6.12.556.12.55

CVSS provenance

osv7.8HIGH
vendor_ubuntu7.8HIGH
vendor_msrc7.1HIGH
vendor_redhat5.5LOW
Stop checking back — get the weekly exploitation signal.

Every Monday: what got weaponized or added to CISA KEV in the last seven days — each CVE cross-linked to its PoC, Nuclei template, and detection rule. Free, one email a week, unsubscribe in one click.