linux-cve-announce - CVE-2025-68760: iommu/amd: Fix potential out-of-bounds read in iommu_mmio

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Message-ID: <2026010551-CVE-2025-68760-5350@gregkh>
Date: Mon,  5 Jan 2026 10:32:56 +0100
From: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To: linux-cve-announce@...r.kernel.org
Cc: Greg Kroah-Hartman <gregkh@...nel.org>
Subject: CVE-2025-68760: iommu/amd: Fix potential out-of-bounds read in iommu_mmio_show

From: Greg Kroah-Hartman <gregkh@...nel.org>

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

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

iommu/amd: Fix potential out-of-bounds read in iommu_mmio_show

In iommu_mmio_write(), it validates the user-provided offset with the
check: `iommu->dbg_mmio_offset > iommu->mmio_phys_end - 4`.
This assumes a 4-byte access. However, the corresponding
show handler, iommu_mmio_show(), uses readq() to perform an 8-byte
(64-bit) read.

If a user provides an offset equal to `mmio_phys_end - 4`, the check
passes, and will lead to a 4-byte out-of-bounds read.

Fix this by adjusting the boundary check to use sizeof(u64), which
corresponds to the size of the readq() operation.

The Linux kernel CVE team has assigned CVE-2025-68760 to this issue.


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

	Issue introduced in 6.17 with commit 7a4ee419e8c144b747a8915856e91a034d7c8f34 and fixed in 6.17.13 with commit b959df804c33913dbfdb90750f2d693502b3d126
	Issue introduced in 6.17 with commit 7a4ee419e8c144b747a8915856e91a034d7c8f34 and fixed in 6.18.2 with commit 0ec4aaf5f3f559716a6559f3d6d9616e9470bed6
	Issue introduced in 6.17 with commit 7a4ee419e8c144b747a8915856e91a034d7c8f34 and fixed in 6.19-rc1 with commit a0c7005333f9a968abb058b1d77bbcd7fb7fd1e7

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-2025-68760
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/iommu/amd/debugfs.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/b959df804c33913dbfdb90750f2d693502b3d126
	https://git.kernel.org/stable/c/0ec4aaf5f3f559716a6559f3d6d9616e9470bed6
	https://git.kernel.org/stable/c/a0c7005333f9a968abb058b1d77bbcd7fb7fd1e7