CVE-2026-89965

Description

In the Linux kernel, the following vulnerability has been resolved: nvdimm/btt: reject an arena whose nfree is below the lane count The BTT info block's nfree field, the number of reserve free blocks, is read from the medium without validation. btt_freelist_init() and btt_rtt_init() size the per-lane freelist[] and rtt[] arrays by nfree, but the I/O path indexes them by the lane from nd_region_acquire_lane(), which is bounded by nd_region->num_lanes (ND_MAX_LANES), not by nfree. A crafted or foreign arena whose nfree is below the lane count makes freelist[lane]/rtt[lane] run past the allocation: an out-of-bounds write. btt.rst documents the nlanes = min(nfree, num_cpus) invariant, which the code does not currently honor: num_lanes is ND_MAX_LANES regardless of nfree. Reject an arena whose nfree is below num_lanes at discovery, before the per-lane arrays are allocated, enforcing that invariant.

Gravité et risque d'exploitation

CVE-2026-89965 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 5.8 % des CVE référencées.

Que faire ?

• Vérifiez si Linux (versions <=6.1.*, <=6.12.*, <4.2, <6a1f2e5ed9267ca19187038ac635393c165213ac, 5.15.221, 5.10.270, 0, 6.1.188, 6.18.51, <9dfa11cef4750b67591307f2c62e47a23d60e4b7, <6b1faf1f099f7060b5f1f2f0d024132581f1726e, <59d5cd1f42b4bab3609512c3cb3d3540d3d21da7, <=5.10.*, <=6.6.*, 7.2.5, 6.6.157, 5212e11fde4d40fa627668b4f2222d20db488f71, <=6.18.*, <f9bf05c63b77d000e9c01f3e47af36973887d350, 6.12.110, 4.2, <=7.2.*, <eb491343d2d1784121ad9af91c25b338c28913c3, <=*, <=5.15.*, <f6c5313aae794ecca8f762c1a3493de5c266f120, <6f79d1a5f2611a3d36e9312be5425cd9cb397c51, 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/eb491343d2d1784121ad9af91c25b338c28913c3
• https://git.kernel.org/stable/c/59d5cd1f42b4bab3609512c3cb3d3540d3d21da7
• https://git.kernel.org/stable/c/f6c5313aae794ecca8f762c1a3493de5c266f120
• https://git.kernel.org/stable/c/f9bf05c63b77d000e9c01f3e47af36973887d350
• https://git.kernel.org/stable/c/6f79d1a5f2611a3d36e9312be5425cd9cb397c51
• https://git.kernel.org/stable/c/6b1faf1f099f7060b5f1f2f0d024132581f1726e
• https://git.kernel.org/stable/c/9dfa11cef4750b67591307f2c62e47a23d60e4b7
• https://git.kernel.org/stable/c/6a1f2e5ed9267ca19187038ac635393c165213ac