---
cve: "CVE-2026-89803"
severity: "HIGH"
cvss: 7.8
epss: "32.5%"
vendor: "Linux"
kev: false
exploited: false
published: "2026-09-16 11:16:45"
tags: [cve, security, high]
source: tsecurity.de CVE-Dossier
exported: "2026-09-19T14:07:38+02:00"
---

# CVE-2026-89803

> 7.8 HIGH

## Beschreibung

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.

## CVSS-Vektor

```
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
```

| Metrik | Wert | Bewertung |
|---|---|---|
| AV Angriffsvektor | Lokal | good |
| AC Komplexität | Gering | bad |
| PR Privilegien | Gering | warn |
| UI Interaktion | Keine | bad |
| S Scope | Unverändert | good |
| C Vertraulichkeit | Hoch | bad |
| I Integrität | Hoch | bad |
| A Verfügbarkeit | Hoch | bad |

## Patch verfügbar (OSV)

- Kernel ≥ 6.12.110
- Kernel ≥ 6.18.51
- Kernel ≥ 7.2.5

## Referenzen

- <https://git.kernel.org/stable/c/f5a79a9ebfbafb87ca7a896e8d6b5f33a98d097e>
- <https://git.kernel.org/stable/c/f3830fdd6930e233d727f29eee1617f7e6a0e9e5>
- <https://git.kernel.org/stable/c/1fef7553dc628295c1208a4f2ac2094c62886e5d>
- <https://git.kernel.org/stable/c/511585987d27d8cb668acebd399fc4deda23404c>

---
_Exportiert aus dem [tsecurity.de CVE-Dossier](https://tsecurity.de/cve?cve=CVE-2026-89803) · Datenquellen: EUVD (ENISA), NVD, OSV, CISA KEV, FIRST EPSS, Exploit-DB, BSI BITS_