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.
Advisories

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Fixes

Solution

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Workaround

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History

Tue, 06 Jan 2026 00:15:00 +0000


Mon, 05 Jan 2026 10:00:00 +0000

Type Values Removed Values Added
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.
Title iommu/amd: Fix potential out-of-bounds read in iommu_mmio_show
First Time appeared Linux
Linux linux Kernel
CPEs cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
Vendors & Products Linux
Linux linux Kernel
References

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cve-icon MITRE

Status: PUBLISHED

Assigner: Linux

Published:

Updated: 2026-01-05T09:32:32.894Z

Reserved: 2025-12-24T10:30:51.033Z

Link: CVE-2025-68760

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Received

Published: 2026-01-05T10:15:57.123

Modified: 2026-01-05T10:15:57.123

Link: CVE-2025-68760

cve-icon Redhat

Severity :

Publid Date: 2026-01-05T00:00:00Z

Links: CVE-2025-68760 - Bugzilla

cve-icon OpenCVE Enrichment

No data.

Weaknesses

No weakness.