CVE-2026-89558
Vulnérabilité critique dans Linux (Linux)
Description
In the Linux kernel, the following vulnerability has been resolved: md/raid10: fix still_degraded being inverted in raid10_sync_request() Commit fe6a19d40ceb ("md/md-bitmap: merge md_bitmap_start_sync() into bitmap_operations") converted still_degraded from int to bool, but inverted the assignment in the loop that checks whether the array will still be degraded after the current device is recovered: "still_degraded = 1" became "still_degraded = false". As a result, recovering a device while another mirror is still missing calls md_bitmap_start_sync() with degraded == false, which clears bitmap bits that the still-missing device needs. When that device is re-added, its bitmap-based recovery finds the bits already cleared and skips every region written while the array was degraded, so it is marked In_sync while holding stale data: silent corruption. Reproducer (raid10 near=2, 4 disks, internal bitmap): - fail and remove one disk of each mirror pair - write to the degraded array - re-add both disks and let recovery finish - "check" reports mismatch_cnt=262272 after 256 MiB of degraded writes and file contents differ; the second disk's "recovery" completes in milliseconds because everything is skipped The same conversion in raid1 got it right (still_degraded = true). Restore the correct value.
Gravité et risque d'exploitation
CVE-2026-89558 obtient un score CVSS de 9.8/10, soit une gravité critique. Selon le modèle EPSS, la probabilité qu'elle soit exploitée dans les 30 prochains jours est de 0.64 %, ce qui la place devant 49.4 % des CVE référencées.
Que faire ?
- Vérifiez si Linux (versions 6.12, <=*, <=6.12.*, <0efabe6229dc683dbf6eeebd0f9fddc7971ed420, fe6a19d40ceb44281905485f56dda715e3214e0e, <=6.18.*, <9bb8da6ecb330a5b1ac9b96f1e55f134a7aef1d4, 6.18.50, 0, <00449d752bee9c8787f42ea1bf533a9fb17f9b6b, <6.12, <=7.2.*, 6.12.109, 7.2.4, <47f1441b281decde6954a2fa82b4131637d685ac, 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.