CVE-2026-68155

Description

In the Linux kernel, the following vulnerability has been resolved: libceph: Reject monmaps advertising zero monitors A message of type CEPH_MSG_MON_MAP contains a monmap that is sent from a monitor to the client. This monmap contains information about the existing monitors in the cluster. Currently, a monmap indicating that there are zero monitors in the cluster is treated as valid. However, it is impossible to have zero monitors in the cluster and still receive a valid monmap from a monitor. Therefore, such a monmap must be corrupted and should be treated as invalid. Furthermore, a monmap with a monitor count of zero can subsequently crash the client when attempting to open a session with a monitor in __open_session(). This happens because the "BUG_ON(monc->monmap->num_mon < 1)" assertion in pick_new_mon() is triggered. This patch extends a check in ceph_monmap_decode() to also reject arriving mon_maps with num_mon == 0 rather than only with num_mon > CEPH_MAX_MON. [ idryomov: drop "log output for unusual values of num_mon" part ]

Gravité et risque d'exploitation

CVE-2026-68155 obtient un score CVSS de 7.5/10, soit une gravité élevée. Selon le modèle EPSS, la probabilité qu'elle soit exploitée dans les 30 prochains jours est de 0.70 %, ce qui la place devant 52.1 % des CVE référencées.

Que faire ?

• Vérifiez si Linux (versions <=6.1.*, <=6.12.*, 6.12.101, <ba5f0015bfd376d764163045a61c17be75f44dae, 0, <=7.1.*, <2.6.34, <0591a15815b498be628a937146e44487d599ba33, 5.15.216, <e67e8b694872c9bc66996040f9de9242f6236ed9, 5.10.271, <=5.10.*, <=6.6.*, ba75bb98cfb93b62c54af25bf67ff90857264bbe, <3b249546f59c3d6d3592c10657f82bc3f1faa07c, 2.6.34, 6.18.42, 7.1.6, 6.1.183, <caf082ef8609a6ac26159ce115f55ab7d00231a3, <=6.18.*, <cd0d41bc569632eaaeccde9d2a6bc919ec00c407, <40480eee361ed9676b3f844d532ac28b47251634, <=*, <=5.15.*, 6.6.148, 7.2, <e3ccd4ecab09b22f507f49cb7ed9990c7158ceab) 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/ba5f0015bfd376d764163045a61c17be75f44dae
• https://git.kernel.org/stable/c/caf082ef8609a6ac26159ce115f55ab7d00231a3
• https://git.kernel.org/stable/c/e3ccd4ecab09b22f507f49cb7ed9990c7158ceab
• https://git.kernel.org/stable/c/0591a15815b498be628a937146e44487d599ba33
• https://git.kernel.org/stable/c/cd0d41bc569632eaaeccde9d2a6bc919ec00c407
• https://git.kernel.org/stable/c/e67e8b694872c9bc66996040f9de9242f6236ed9
• https://git.kernel.org/stable/c/3b249546f59c3d6d3592c10657f82bc3f1faa07c
• https://git.kernel.org/stable/c/40480eee361ed9676b3f844d532ac28b47251634