CVE-2026-64042: vfio/pci: Check BAR resources before exporting a DMABUF
In the Linux kernel, the following vulnerability has been resolved:
vfio/pci: Check BAR resources before exporting a DMABUF
A DMABUF exports access to BAR resources and, although they are requested at startup time, we need to ensure they really were reserved before exporting. Otherwise, it's possible to access unreserved resources through the export.
Add a check to the DMABUF-creation path.
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Compensating control
In the vfio/pci DMABUF-creation path, check BAR resources before exporting a DMABUF and ensure the requested resources were reserved at startup before allowing the export.
Event History
Frequently Asked Questions
Who is exposed to this issue?
Systems using the Linux kernel's vfio/pci DMABUF export functionality are exposed when a BAR resource is not actually reserved but is still exported. The issue is local, and the supplied vector indicates that an attacker needs low-privileged local access.
What does an attacker need to exploit it?
The attacker needs local access with low privileges and must be able to reach the vfio/pci DMABUF-creation path. No user interaction is required.
What is the impact of successful exploitation?
Successful exploitation can provide access to unreserved BAR resources through a DMABUF export. The reported severity vector indicates high confidentiality, integrity, and availability impact, with scope changed.
What should be changed to address the issue?
Apply a Linux kernel update containing the vfio/pci change that verifies BAR resources are reserved before allowing DMABUF creation. The referenced stable kernel commits contain the fix.