CVE-2026-64511: ACPI: NFIT: core: Fix possible NULL pointer dereference

From: Greg Kroah-Hartman <[email protected]>

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

In the Linux kernel, the following vulnerability has been resolved:

ACPI: NFIT: core: Fix possible NULL pointer dereference

After commit 9b311b7313d6 ("ACPI: NFIT: Install Notify() handler before
getting NFIT table"), acpi_nfit_probe() installs an ACPI notify handler
for the NFIT device before checking the presence of the NFIT table.  If
that table is not there, 0 is returned without allocating the acpi_desc
object and setting the driver data pointer of the NFIT device.  If the
platform firmware triggers an NFIT_NOTIFY_UC_MEMORY_ERROR notification
on the NFIT device at that point, acpi_nfit_uc_error_notify() will
dereference a NULL pointer.

Prevent that from occurring by adding an acpi_desc check against NULL
to acpi_nfit_uc_error_notify().

The Linux kernel CVE team has assigned CVE-2026-64511 to this issue.


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

	Issue introduced in 6.6 with commit 9b311b7313d6c104dd4a2d43ab54536dce07f960 and fixed in 6.6.145 with commit a44343fe230aa48c74ef09830f3c5c90848b257e
	Issue introduced in 6.6 with commit 9b311b7313d6c104dd4a2d43ab54536dce07f960 and fixed in 6.12.96 with commit 3c8f73b0fbdf956c98e2329d5aaea3ad09a9cfb6
	Issue introduced in 6.6 with commit 9b311b7313d6c104dd4a2d43ab54536dce07f960 and fixed in 6.18.39 with commit 452945662fd8e9862a2d2043239c7ee1815d1ac4
	Issue introduced in 6.6 with commit 9b311b7313d6c104dd4a2d43ab54536dce07f960 and fixed in 7.1.4 with commit 873576e585da5d0fc5debbab74eed565c0acea99
	Issue introduced in 6.6 with commit 9b311b7313d6c104dd4a2d43ab54536dce07f960 and fixed in 7.2-rc1 with commit 027e128abb82788189d6d45b68e3e8e7329b67be

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-2026-64511
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/acpi/nfit/core.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/a44343fe230aa48c74ef09830f3c5c90848b257e
	https://git.kernel.org/stable/c/3c8f73b0fbdf956c98e2329d5aaea3ad09a9cfb6
	https://git.kernel.org/stable/c/452945662fd8e9862a2d2043239c7ee1815d1ac4
	https://git.kernel.org/stable/c/873576e585da5d0fc5debbab74eed565c0acea99
	https://git.kernel.org/stable/c/027e128abb82788189d6d45b68e3e8e7329b67be