# CVE-2021-47327: linux: In the Linux kernel, the following vulnerability has been resolved:  iommu/arm-smmu: Fix arm_smmu_device refcount lea...

CVE-2021-47327 is fixed in linux on 1 platform, first by DEBIAN-CVE-2021-47327, released May 21, 2024. It is not reported as exploited. Patch Radar priority: High.

- Web page: https://patchblox.com/security/cve/CVE-2021-47327
- Priority: High
- CVSS: 7.1 (high)
- EPSS: 0.0026
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: May 21, 2024

## Description

In the Linux kernel, the following vulnerability has been resolved:  iommu/arm-smmu: Fix arm_smmu_device refcount leak when arm_smmu_rpm_get fails  arm_smmu_rpm_get() invokes pm_runtime_get_sync(), which increases the refcount of the "smmu" even though the return value is less than 0.  The reference counting issue happens in some error handling paths of arm_smmu_rpm_get() in its caller functions. When arm_smmu_rpm_get() fails, the caller functions forget to decrease the refcount of "smmu" increased by arm_smmu_rpm_get(), causing a refcount leak.  Fix this issue by calling pm_runtime_resume_and_get() instead of pm_runtime_get_sync() in arm_smmu_rpm_get(), which can keep the refcount balanced in case of failure.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | linux Debian 12.15 (bookworm) | 5.14.6-1 | [DEBIAN-CVE-2021-47327](https://patchblox.com/security/data/fix/linux/debian-cve-2021-47327.md) | May 21, 2024 |
| Linux | linux Debian 13.5 (trixie) | 5.14.6-1 | [DEBIAN-CVE-2021-47327](https://patchblox.com/security/data/fix/linux/debian-cve-2021-47327.md) | May 21, 2024 |
| Linux | linux Debian 14 | 5.14.6-1 | [DEBIAN-CVE-2021-47327](https://patchblox.com/security/data/fix/linux/debian-cve-2021-47327.md) | May 21, 2024 |

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