CVE-2025-68760

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BaseFortify

Publication date: 2026-01-05

Last updated on: 2026-01-08

Assigner: kernel.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.

CVSS Scores

EPSS Scores

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Meta Information

Published

2026-01-05

Last Modified

2026-01-08

Generated

2026-07-06

AI Q&A

2026-01-05

EPSS Evaluated

2026-07-05

NVD

CVE-2025-68760

EUVD

EUVD-2026-0890

Affected Vendors & Products

Vendor	Product	Version / Range
linux	linux_kernel	*

Helpful Resources

Exploitability

CWE

KEV

CWE ID	Description
CWE-UNKNOWN

Attack-Flow Graph

Executive Summary

This vulnerability is a potential out-of-bounds read in the Linux kernel's iommu/amd component. Specifically, the function iommu_mmio_write() validates a user-provided offset assuming a 4-byte access, but the corresponding iommu_mmio_show() function performs an 8-byte read. If a user provides an offset at the boundary (mmio_phys_end - 4), the check passes incorrectly, leading to a 4-byte out-of-bounds read. The fix involved adjusting the boundary check to match the 8-byte read size.

Impact Analysis

This vulnerability can lead to an out-of-bounds read in kernel memory, which may cause information disclosure or system instability. An attacker could potentially exploit this to read unintended memory areas, possibly leaking sensitive information or causing a denial of service.

Mitigation Strategies

To mitigate this vulnerability, update the Linux kernel to a version that includes the fix for the iommu/amd out-of-bounds read issue. The fix involves adjusting the boundary check in iommu_mmio_write() to correctly handle 8-byte reads, preventing out-of-bounds access. Until the update is applied, restrict untrusted user access to the affected iommu interfaces to minimize risk.

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