CVE-2026-90326
Vulnérabilité élevée dans Linux (Linux)
Description
In the Linux kernel, the following vulnerability has been resolved: blk-cgroup: fix race between policy activation and blkg destruction When switching an IO scheduler on a block device, blkcg_activate_policy() allocates blkg_policy_data (pd) for all blkgs attached to the queue. However, blkcg_activate_policy() may race with concurrent blkcg deletion, leading to use-after-free and memory leak issues. The use-after-free occurs in the following race: T1 (blkcg_activate_policy): - Successfully allocates pd for blkg1 (loop0->queue, blkcgA) - Fails to allocate pd for blkg2 (loop0->queue, blkcgB) - Enters the enomem rollback path to release blkg1 resources T2 (blkcg deletion): - blkcgA is deleted concurrently - blkg1 is freed via blkg_free_workfn() - blkg1->pd is freed T1 (continued): - Rollback path accesses blkg1->pd->online after pd is freed - Triggers use-after-free In addition, blkg_free_workfn() frees pd before removing the blkg from q->blkg_list. This allows blkcg_activate_policy() to allocate a new pd for a blkg that is being destroyed, leaving the newly allocated pd unreachable when the blkg is finally freed. Fix these races by extending blkcg_mutex coverage to serialize blkcg_activate_policy() rollback and blkg destruction, ensuring pd lifecycle is synchronized with blkg list visibility.
Gravité et risque d'exploitation
CVE-2026-90326 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 6.0 % des CVE référencées.
Que faire ?
- Vérifiez si Linux (versions <=6.1.*, 6.1.17, 6.1.16, 6.2.4, 0, <ac34e655dffa74349d885a43d098115336f53842, 6.18.52, bfe46d2efe46c5c952f982e2ca94fe2ec5e58e2a, <6.1.17, <6.3, f1c006f1c6850c14040f8337753a63119bba39b9, <5313d4d41739b0cb63000747c97bb1217ac45f3e, <6.2.4, 6.2.3, 6.3, 7.2.6, 81c1188905f88b77743d1fdeeedfc8cb7b67787d, <083b58373463a6e5ee60ecb135269348f68ad7df, <=6.18.*, <=6.2.*, <2cf9f50a38c1839e549a08e22aa35e8d69e2c8fd, <=7.2.*, <=*, <b5dae1cd0d8368b4338430ff93403df67f0b8bcc, 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/b5dae1cd0d8368b4338430ff93403df67f0b8bcc
- https://git.kernel.org/stable/c/083b58373463a6e5ee60ecb135269348f68ad7df
- https://git.kernel.org/stable/c/ac34e655dffa74349d885a43d098115336f53842
- https://git.kernel.org/stable/c/2cf9f50a38c1839e549a08e22aa35e8d69e2c8fd
- https://git.kernel.org/stable/c/5313d4d41739b0cb63000747c97bb1217ac45f3e