CVE-2026-98841
CVE-2026-98841CVE-2026-98841
Description
In the Linux kernel, the following vulnerability has been resolved:
virt: vmgenid: set driver_data before registering notification handlers
Both probe paths register their notification handler before assigning
driver_data, which the handler dereferences.
In the devicetree path, the notification IRQ can fire as soon as
devm_request_irq() registers the handler: the interrupt may already be
pending at probe time, for example when a VMM injects the
generation-changed notification while restoring a guest from a snapshot
that was taken before the driver had probed (Firecracker does exactly
this on snapshot restore). The IRQ is also requested with IRQF_SHARED,
so another device sharing the line can trigger the handler just as
early. The handler then calls vmgenid_notify(), which dereferences the
still-NULL driver_data and panics:
Unable to handle kernel NULL pointer dereference at virtual address 0000000000000010
CPU: 0 UID: 0 PID: 1 Comm: swapper/0 Not tainted 6.18.38+ #1 PREEMPT(non
Scoring
| Last modified | 2026-10-18 |