CVE-2026-46034vfio/cdx: Fix NULL pointer dereference in interrupt trigger path

Official description

In the Linux kernel, the following vulnerability has been resolved: vfio/cdx: Fix NULL pointer dereference in interrupt trigger path Add validation to ensure MSI is configured before accessing cdx_irqs array in vfio_cdx_set_msi_trigger(). Without this check, userspace can trigger a NULL pointer dereference by calling VFIO_DEVICE_SET_IRQS with VFIO_IRQ_SET_DATA_BOOL or VFIO_IRQ_SET_DATA_NONE flags before ever setting up interrupts via VFIO_IRQ_SET_DATA_EVENTFD. The vfio_cdx_msi_enable() function allocates the cdx_irqs array and sets config_msi to 1 only when called through the EVENTFD path. The trigger loop (for DATA_BOOL/DATA_NONE) assumed this had already been done, but there was no enforcement of this call ordering. This matches the protection used in the PCI VFIO driver where vfio_pci_set_msi_trigger() checks irq_is() before the trigger loop.

Affected packages & fixed versions

Affected products (as reported)

References

• https://git.kernel.org/stable/c/51bf7638f33aece41cb3f4cbeb942cc52950e329
• https://git.kernel.org/stable/c/5d6c349c9823eb819fed8b537b088cf38126018c
• https://git.kernel.org/stable/c/338a736aaf15e8ba3635ce20b29af5b8fc15e66a
• https://git.kernel.org/stable/c/5ea5880764cbb164afb17a62e76ca75dc371409d