CVE-2026-64042: vfio/pci: Check BAR resources before exporting a DMABUF

Greg Kroah-Hartman <[email protected]>
Newsgroups org.kernel.vger.linux-cve-announce
Message-ID <2026071906-CVE-2026-64042-c30f@gregkh>
From: Greg Kroah-Hartman <[email protected]>

Description
===========

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.

The Linux kernel CVE team has assigned CVE-2026-64042 to this issue.


Affected and fixed versions
===========================

	Issue introduced in 6.19 with commit 5d74781ebc86c5fa9e9d6934024c505412de9b52 and fixed in 7.0.11 with commit 8443cd4497a4498c4b01058d76a92116244cb605
	Issue introduced in 6.19 with commit 5d74781ebc86c5fa9e9d6934024c505412de9b52 and fixed in 7.1 with commit 702809dabdecca807bdd50cfdcc1c980feb2ba62

Please see https://www.kernel.org for a full list of currently supported
kernel versions by the kernel community.

Unaffected versions might change over time as fixes are backported to
older supported kernel versions.  The official CVE entry at
	https://cve.org/CVERecord/?id=CVE-2026-64042
will be updated if fixes are backported, please check that for the most
up to date information about this issue.


Affected files
==============

The file(s) affected by this issue are:
	drivers/vfio/pci/vfio_pci_dmabuf.c


Mitigation
==========

The Linux kernel CVE team recommends that you update to the latest
stable kernel version for this, and many other bugfixes.  Individual
changes are never tested alone, but rather are part of a larger kernel
release.  Cherry-picking individual commits is not recommended or
supported by the Linux kernel community at all.  If however, updating to
the latest release is impossible, the individual changes to resolve this
issue can be found at these commits:
	https://git.kernel.org/stable/c/8443cd4497a4498c4b01058d76a92116244cb605
	https://git.kernel.org/stable/c/702809dabdecca807bdd50cfdcc1c980feb2ba62
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