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CVE-2025-40105

Vulnérabilité élevée dans Linux (Linux)

CVSS 7.8 · Élevée
EPSS 0.2%
Linux•Linux•Versions : <=6.1.*, <=6.12.*, <4.16, 0, 6.6.114, <b5abafd0aa8d7bcb935c8f91e4cfc2f2820759e4, 6.18, <=5.10.*, <=6.6.*, <20863bb7fbb016379f8227122edfabc5c799bc79, <=5.4.*, <7e0c8aaf4e28918abded547a5147c7d52c4af7d2, <eadc49999fa994d6fbd70c332bd5d5051cc42261, 6.1.158, 5.10.246, <8004d4b8cbf1bd68a23c160d57287e177c82cc69, 4.16, <cebfbf40056a4d858b2a3ca59a69936d599bd209, <=*, <=5.15.*, <=6.17.*, 5.4.301, <56094ad3eaa21e6621396cc33811d8f72847a834, 5.15.196, <620f3b0ede9c5cb4976cd0457d0b04ad551e5d6b, 6.17.5, f1ee616214cb22410e939d963bbb2349c2570f02, 6.12.55

Description

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.

Gravité et risque d'exploitation

CVE-2025-40105 obtient un score CVSS de 7.8/10, soit une gravité élevée. Selon le modèle EPSS, la probabilité qu'elle soit exploitée dans les 30 prochains jours est de 0.17 %, ce qui la place devant 5.4 % des CVE référencées.

Que faire ?

  • Vérifiez si Linux (versions <=6.1.*, <=6.12.*, <4.16, 0, 6.6.114, <b5abafd0aa8d7bcb935c8f91e4cfc2f2820759e4, 6.18, <=5.10.*, <=6.6.*, <20863bb7fbb016379f8227122edfabc5c799bc79, <=5.4.*, <7e0c8aaf4e28918abded547a5147c7d52c4af7d2, <eadc49999fa994d6fbd70c332bd5d5051cc42261, 6.1.158, 5.10.246, <8004d4b8cbf1bd68a23c160d57287e177c82cc69, 4.16, <cebfbf40056a4d858b2a3ca59a69936d599bd209, <=*, <=5.15.*, <=6.17.*, 5.4.301, <56094ad3eaa21e6621396cc33811d8f72847a834, 5.15.196, <620f3b0ede9c5cb4976cd0457d0b04ad551e5d6b, 6.17.5, f1ee616214cb22410e939d963bbb2349c2570f02, 6.12.55) est présent sur votre parc.
  • Appliquez le correctif ou la version corrigée indiqués dans les références de l'éditeur.
  • À défaut de correctif, limitez l'exposition (filtrage réseau, désactivation du composant).
  • Automatisez la détection : les agents CVE Heimdall (gratuits, open source) corrèlent l'inventaire de vos serveurs avec la base CVE.

Références

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