CVE-2026-90006

Description

In the Linux kernel, the following vulnerability has been resolved: samples/damon/mtier: handle damon_stop() failure damon_sample_mtier_stop() assumes its damon_stop() call will always successfully stops the two DAMON contexts. Hence it deallocates the two DAMON contexts after the damon_stop() call. However, if a given context is already stopped, damon_stop() fails and returns an error while letting the DAMON contexts that have not yet stopped keep running. This kind of unexpected early DAMON context stops could happen due to memory allocation failures in kdamond_fn(). Because damon_sample_mtier_stop() just deallocates all DAMON contexts with damon_target and damon_region objects that are linked to the contexts, the execution of the unstopped DAMON context (kdamond) ends up using the memory that freed (use-after-free). Fix the issue by separating the damon_stop() to be invoked per context. Note that DAMON_SYSFS also allows multiple DAMON contexts execution. But, it calls damon_stop() for each context one by one. Hence this issue is only in mtier. For the long term, it would be better to refactor damon_stop() to always ensure stopping all contexts regardless of the failures in the middle. Make this fix in the current way, though, to keep it simple and easy to backport. I will do the refactoring later. The issue was discovered [1] by Sashiko.

Gravité et risque d'exploitation

CVE-2026-90006 obtient un score CVSS de 0.0/10, soit une gravité non évaluée. Selon le modèle EPSS, la probabilité qu'elle soit exploitée dans les 30 prochains jours est de 0.22 %, ce qui la place devant 12.0 % des CVE référencées.

Que faire ?

• Vérifiez si Linux (versions <6.16, 6.18.51, <215f9a7e4f1dcfc05ebcdc5c1ad0ea0dcb47bd09, <=*, 6.16, <=7.2.*, <=6.18.*, 82a08bde3cf7bbbe90de57baa181bebf676582c7, 0, 7.2.5, <9dc5b6d66fd51b103eff21ed0df3e292f489ebc0, <3c07c57b894116ae26f01b84c68e68b538ada7ed, 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/3c07c57b894116ae26f01b84c68e68b538ada7ed
• https://git.kernel.org/stable/c/215f9a7e4f1dcfc05ebcdc5c1ad0ea0dcb47bd09
• https://git.kernel.org/stable/c/9dc5b6d66fd51b103eff21ed0df3e292f489ebc0