CVE-2026-72389

Description

In the Linux kernel, the following vulnerability has been resolved: bridge: stp: Fix a potential use-after-free when deleting a bridge The three STP timers are not supposed to be armed while the bridge is administratively down. They are synchronously deactivated when the bridge is put administratively down and the various call sites check for 'IFF_UP' before arming them. This check is missing from br_topology_change_detection() and it is possible to engineer a situation in which the topology change timer is armed while the bridge is administratively down, resulting in a use-after-free [1] when the bridge is deleted. Fix by adding the missing check and for good measures synchronously shutdown the three timers when the bridge is deleted. [1] ODEBUG: free active (active state 0) object: ffff88811662b9b0 object type: timer_list hint: br_topology_change_timer_expired (net/bridge/br_stp_timer.c:120) WARNING: lib/debugobjects.c:629 at debug_print_object+0x1bc/0x450, CPU#9: ip/359

Gravité et risque d'exploitation

CVE-2026-72389 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 0.16 %, ce qui la place devant 5.3 % des CVE référencées.

Que faire ?

• Vérifiez si Linux (versions <40cbfa3a28e0919469d1b086629bb3ce38a83593, <=6.1.*, 7.1.5, <b4b3458ef88df4798632619f018791d4344bcd92, <=6.12.*, 6.18.40, 2.6.12, <2a00517db8de4be7df3d483b215c5544fb30a191, 0, <=7.1.*, <2.6.12, 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, 6.1.178, 6.12.97, <=6.6.*, <c86579b0a2d201792bcb59316629f4ba4758cfc8, <=6.18.*, <297a747f59bff6573196d7236178144d66524e68, 5.15.212, 6.6.145, <=*, <39283907a25e5caf0f2bd2947f6e56644b01e2b7, <=5.15.*, 7.2, <4c40eec06eeac37c58e47a6058eb32901218d5d4) 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/c86579b0a2d201792bcb59316629f4ba4758cfc8
• https://git.kernel.org/stable/c/297a747f59bff6573196d7236178144d66524e68
• https://git.kernel.org/stable/c/4c40eec06eeac37c58e47a6058eb32901218d5d4
• https://git.kernel.org/stable/c/39283907a25e5caf0f2bd2947f6e56644b01e2b7
• https://git.kernel.org/stable/c/b4b3458ef88df4798632619f018791d4344bcd92
• https://git.kernel.org/stable/c/40cbfa3a28e0919469d1b086629bb3ce38a83593
• https://git.kernel.org/stable/c/2a00517db8de4be7df3d483b215c5544fb30a191