iommu/arm-smmu: Fix arm_smmu_device refcount leak when arm_smmu_rpm_get fails
Key facts
- Attack vector
- Local
- Privileges required
- Low
- User interaction
- None
- Attack complexity
- Low
- Impact type
- —
- Confidentiality · integrity · availability
- High · None · High
- Fix status
- Partial Red Hat: 2 without a fix
Attack profile from CVSS 3.1 · CISA ADP. Fix status from CNA and Red Hat.
Summary
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.
Why it matters now
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- No
- Technical impact
- Partial
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| Linux | Linux | 5.0 and later | 5.4.134, 5.10.52, 5.12.19, 5.13.4, 5.14 | Patch available | CNA |
- Linux VendorLinux Affected 5.0 and later Fixed in 5.4.134, 5.10.52, 5.12.19, 5.13.4, 5.14 Patch available CNA
CPE configurations NVD · 1
| CPE | Versions | Role | Vendor |
|---|---|---|---|
| cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* | before 5.4.134; 5.5 to before 5.10.52; 5.11 to before 5.12.19; 5.13 to before 5.13.4 | Vulnerable | Linux |
- cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* Versions before 5.4.134; 5.5 to before 5.10.52; 5.11 to before 5.12.19; 5.13 to before 5.13.4 Vulnerable ·Linux
Remediation
- Fix · CNA Linux (Linux) Fixed in 5.4.134, 5.10.52, 5.12.19, 5.13.4, 5.14
Vendor assessments
Red Hat
Red Hat rating: Low. Red Hat's page for this CVE →
| Product | Status | Plan or fix |
|---|---|---|
| Red Hat Enterprise Linux 8 | Affected | No fix yet |
| Red Hat Enterprise Linux 9 | Affected | No fix yet |
Not affected: 3 products
- Red Hat Enterprise Linux 6
- Red Hat Enterprise Linux 7
- Red Hat Enterprise Linux 9
Timeline
- 2026-10-02 Threatist record created from CVE-2021-47327
- 2026-10-03 Alias added: GHSA-8w7w-2rv7-qqw7
References
Patch 5
- https://git.kernel.org/stable/c/3761ae0d0e549f2acdaf11f49df4ed06d256b20f
- https://git.kernel.org/stable/c/c4007596fbdabc29f858dc2e1990858a146b60b2
- https://git.kernel.org/stable/c/fbf4daa6f4105e01fbd3868006f65c163365c1e3
- https://git.kernel.org/stable/c/fe92c058199067ae90cf2a901ddf3c271893557a
- https://git.kernel.org/stable/c/1adf30f198c26539a62d761e45af72cde570413d
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- TI-2013-05264 The (1) get_user and (2) put_user API functions in the Linux kernel before 3.5.5 on the… KEVCVSS 3.1HIGH 8.8
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- TI-2013-01864 The perf_swevent_init function in kernel/events/core.c in the Linux kernel before 3.8.9… KEVCVSS 3.1HIGH 8.4
- TI-2021-05514 Heap Out-Of-Bounds Write in Netfilter IP6T_SO_SET_REPLACE KEVCVSS 3.1HIGH 8.3
Sources
- CVE-2021-47327 · CVE Program
- CVE-2021-47327 · NVD
- FIRST EPSS
- GHSA-8w7w-2rv7-qqw7 · GitHub Advisory Database · CC BY 4.0
- CVE-2021-47327 · Red Hat security data · CC BY 4.0
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences