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.
Conclusion & alert: CVE-2021-47327 is rated Low Risk (34.4/100): CVSS High severity, with low exploitation likelihood (EPSS 0.26%). Mandatory action: Monitor for updates and reassess as exploit intelligence or EPSS changes.
Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.
EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).
| # | Date | Old EPSS score | New EPSS score | Delta (New - Old) |
|---|---|---|---|---|
| 1 | 2026-06-15 | 0.05% | 0.26% | +0.21% |
| 2 | 2025-12-10 | 0.06% | 0.05% | -0.01% |
| 3 | 2025-10-28 | — | 0.06% | — |
Full EPSS history (10 records total)
CVSS metrics for this CVE.
| Base score | Version | Severity | Vector | Exploitability | Impact | Score source |
|---|---|---|---|---|---|---|
| 7.1 | 3.1 | HIGH |
|
1.8 | 5.2 | 134c704f-9b21-4f2e-91b3-4a467353bcc0 |
| vendor | priority | summary | link |
|---|---|---|---|
debian
|
not yet assigned | CVE-2021-47327 not yet assigned priority: Debian including 1 source packages (linux), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 5. | https://security-tracker.debian.org/tracker/CVE-2021-47327 |
redhat
|
low | — | https://access.redhat.com/security/cve/CVE-2021-47327 |
suse
|
low | CVE-2021-47327 severity low: SUSE including 24 source package names (cluster-md-kmp-default, dlm-kmp-default, …), 180 product×package rows across 35 product lines (SUSE Linux Enterprise High Performance Computing 12 SP5, SUSE Linux Enterprise High Performance Computing 15 SP4-ESPOS, … (35 product lines)): Known Not Affected 180. | https://www.suse.com/security/cve/CVE-2021-47327/ |
ubuntu
|
medium | CVE-2021-47327 medium priority: Ubuntu including 160 source packages (linux, linux-allwinner-5.19, …), 1686 status rows across 11 suites (bionic, focal, jammy, mantic, noble, oracular, plucky, questing, trusty, upstream, xenial): DNE 1267, not-affected 146, ignored 129, released 124, needed 20. | https://ubuntu.com/security/CVE-2021-47327 |
| Vendor | Product | Version | Raw CPE |
|---|---|---|---|
| linux | linux_kernel | < 5.4.134 | cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* |
| linux | linux_kernel | >= 5.5, < 5.10.52 | cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* |
| linux | linux_kernel | >= 5.11, < 5.12.19 | cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* |
| linux | linux_kernel | >= 5.13, < 5.13.4 | cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* |