CVE-2026-89803
Vulnérabilité élevée dans Linux (Linux)
Description
In the Linux kernel, the following vulnerability has been resolved: drm/nouveau: unsubscribe the channel-kill event before the fence context nouveau_channel_del() tears the fence context down first and only drops the channel-kill subscription later, in the middle of the nvif object teardown: if (chan->fence) nouveau_fence(chan->cli->drm)->context_del(chan); ... nvif_object_dtor(&chan->vram); nvif_event_dtor(&chan->kill); The subscribed handler is nouveau_channel_killed(), which calls nouveau_channel_kill() and from there nouveau_fence_context_kill() on chan->fence. A kill event delivered in that window takes fctx->lock and walks fctx->pending on a fence context that context_del() has already freed. Nothing reaches this below Fermi today, because the subscription is gated on FERMI_CHANNEL_GPFIFO and nothing kills a channel there. On Fermi and newer the window is real but narrow, since a kill has to land exactly while the channel is being destroyed. That is reason enough on its own, which is why this carries a Fixes: tag. The last patch in this series subscribes Tesla channels as well; nothing kills those today, so it does not widen the exposure now, but it is the groundwork for a recovery path that would, and the ordering is better fixed before that lands than alongside it. Drop the subscription before anything it depends on is torn down.
Gravité et risque d'exploitation
CVE-2026-89803 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 0.16 %, ce qui la place devant 5.2 % des CVE référencées.
Que faire ?
- Vérifiez si Linux (versions 6.18.51, <=*, <1fef7553dc628295c1208a4f2ac2094c62886e5d, <=6.12.*, <=7.2.*, <=6.18.*, 5.6, 7.2.5, <f5a79a9ebfbafb87ca7a896e8d6b5f33a98d097e, 0, 7.3, 6.12.110, <511585987d27d8cb668acebd399fc4deda23404c, ea13e5abf807ea912ce84eef6a1946b9a38c6508, <f3830fdd6930e233d727f29eee1617f7e6a0e9e5, <5.6) 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.