CVE-2026-64057
Vulnérabilité élevée dans Linux (Linux)
Description
In the Linux kernel, the following vulnerability has been resolved: afs: Fix the locking used by afs_get_link() The afs filesystem in the kernel doesn't do locking correctly for symbolic links. There are a number of problems: (1) It doesn't do any locking around afs_read_single() to prevent races between multiple ->get_link() calls, thereby allowing the possibility of leaks. (2) It doesn't use RCU barriering when accessing the buffer pointers during RCU pathwalk. (3) It can race with another thread updating the contents of the symlink if a third party updated it on the server. Fix this by the following means: (0) Move symlink handling into its own file as this makes it more complicated. (1) Take the validate_lock around afs_read_single() to prevent races between multiple ->get_link() calls. (2) Keep a separate copy of the symlink contents with an rcu_head. This is always going to be a lot smaller than a page, so it can be kmalloc'd and save quite a bit of memory. It also needs a refcount for non-RCU pathwalk. (3) Split the symlink read and write-to-cache routines in afs from those for directories. (4) Discard the I/O buffer as soon as the write-to-cache completes as this is a full page (plus a folio_queue). (5) If there's no cache, discard the I/O buffer immediately after reading and copying if there is no cache.
Gravité et risque d'exploitation
CVE-2026-64057 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 0.13 %, ce qui la place devant 2.6 % des CVE référencées.
Que faire ?
- Vérifiez si Linux (versions <=7.0.*, <77ea917cbed62882a33114b1e23ededb977e4287, <=*, 6.18.57, 6.14, 7.1, eae9e78951bb02a7b94a9adef6e981413d13c564, <6.14, <=6.18.*, 7.0.11, <93531bca46707c6c28c4f4eb26c101fa36ccb8cb, 0, <c0410adf3da6db46f3513411fcf95e63c2f1d1ad) 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.