CVE-2026-97556

Description

In the Linux kernel, the following vulnerability has been resolved: smb: client: avoid leaking refcount when cifs_sb_tlink() fails cifs_oplock_break() takes over the reference that cifs_queue_oplock_break() acquired when it queued the work, and drops it with _cifsFileInfo_put() once the break has been processed. Only in setups with "-o multiuser", cifs_sb_tlink() may fail, at which point cifs_oplock_break() returns without putting the file reference, mirroring the reference leak we already fixed in the companion patch to cifs_queue_oplock_break(). This would trigger a crash due to busy inodes on the next unmount: BUG: Dentry ... still in use (1) [unmount of cifs cifs] VFS: Busy inodes after unmount of cifs (cifs) Drop the reference on that path as well. Doing so before the out label mirrors the normal path, which also puts the reference before cifs_done_oplock_break(). Found by Sashiko code review. The failure path was not exercised at runtime.

Gravité et risque d'exploitation

CVE-2026-97556 obtient un score CVSS de 0.0/10, soit une gravité non évaluée. Selon le modèle EPSS, la probabilité qu'elle soit exploitée dans les 30 prochains jours est de 0.21 %, ce qui la place devant 9.8 % des CVE référencées.

Que faire ?

• Vérifiez si Linux (versions e8f5f849ffce24490eb9449e98312b66c0dba76f, <e9c5bcc88b8337157e480c85a6d2f326bc265012, <=6.1.*, <=6.12.*, 7.2.7, <6.5, 6.18.53, 6.4.12, 0, <9ec991e148368e3207e98134c509a625097f7693, 6b67a6d2e50634fe127e656147c81915955e9f5e, 6.5, <dd03fd658ea59821505e0e643b6b7cbdf51c4e1d, 6.6.158, <=6.6.*, 6.1.189, <23b26f4408ac3f35a482d2e5cf6fc865d4201b71, 5ee28bcfbaacf289eb25c662a2862542ea6ce6a7, <1d1b0f1d812a4011a57bc6c70492c34a2e46c6dd, <5.16, <=6.18.*, b99f490ea87ebcca3a429fd8837067feb56a4c7c, 5.15.128, <=7.2.*, <6.1.189, 6.1.47, <=*, <55c5f095d4df14271b238f826e1392fda7b6e60e, 6.12.111, 7.3) 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

• https://git.kernel.org/stable/c/55c5f095d4df14271b238f826e1392fda7b6e60e
• https://git.kernel.org/stable/c/e9c5bcc88b8337157e480c85a6d2f326bc265012
• https://git.kernel.org/stable/c/9ec991e148368e3207e98134c509a625097f7693
• https://git.kernel.org/stable/c/dd03fd658ea59821505e0e643b6b7cbdf51c4e1d
• https://git.kernel.org/stable/c/1d1b0f1d812a4011a57bc6c70492c34a2e46c6dd
• https://git.kernel.org/stable/c/23b26f4408ac3f35a482d2e5cf6fc865d4201b71