Security readout for executives and security teams
Plain-English summary
This is a Linux kernel bug in MediaTek IOMMU power management. On affected kernels, resume and suspend clock handling can become inconsistent and trigger kernel warnings. The sources do not show data theft, privilege escalation, remote attack, or active exploitation.
Executive priority
Treat this as a targeted platform maintenance issue, not an emergency internet-facing risk. Prioritize it where MediaTek-based Linux devices are operationally important or where repeated kernel warnings affect reliability monitoring.
Technical view
The issue is in mtk_iommu_runtime_resume: the clock was not always enabled when m4u_dom was null, allowing runtime suspend to disable an already disabled clock and warn in clk_core_disable. The fix always enables the clock on resume and removes redundant enablement from mtk_iommu_hw_init.
Likely exposure
Exposure appears limited to Linux systems using the MediaTek IOMMU driver on affected 5.12-era kernels or vendor kernels carrying the vulnerable code. Generic servers without MediaTek IOMMU are unlikely to be exposed based on the supplied sources.
Exploitation context
The bundle reports no CVSS, no CWE, and KEV is false. The evidence describes a kernel warning during runtime power management, not a public exploit path. Active exploitation is not supported by the provided sources.
Researcher notes
The source evidence is narrow: a kernel runtime power-management bug and two stable commit references. There is no supplied exploitability analysis, impact rating, or vendor advisory beyond the Linux resolution text.
Mitigation direction
- Inventory Linux devices using MediaTek SoCs or the mtk-iommu driver.
- Identify kernels matching the affected 5.12-era range or vendor backports.
- Apply a vendor kernel update containing the referenced stable fixes.
- If no packaged update exists, check vendor guidance before backporting.
- Prioritize embedded, ChromeOS-like, or appliance fleets using MediaTek hardware.
Validation and detection
- Confirm whether affected systems load the MediaTek IOMMU driver.
- Review kernel logs for infra_m4u or clk_core_disable warnings.
- Verify the referenced stable commits are present in the deployed kernel.
- After updating, retest suspend/resume and confirm warnings do not recur.
Public sources used
Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.
Conservative CVE-to-ATT&CK context
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ATT&CK lookup starting points
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CVE-2021-47025 mapping review
Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.
Open ATT&CK lookup- Severity
- Unknown
- CVSS
- Not scored
- Known Exploited
- No
- Published
CNA and ADP enrichment extracted from CVE v5
These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.
SSVC decision data
Vulnerability timeline
Timeline events are normalized from CVE metadata, CNA source timelines, ADP timelines, and KEV metadata when present.
- CVE reservedCVE Program
The CVE ID was reserved by the assigning CNA.
- CVE publishedCVE Program
The CVE record was published.
- CVE updatedCVE Program
The CVE record metadata indicates this as the latest update time.
ADP provider summaries
Source materials
- CVE List V5 sourceCVE List V5
- https://git.kernel.org/stable/c/5cad9e2caa9613fdcd246bd4ebf0ffbec1cba2caCVE reference, Linux
- https://git.kernel.org/stable/c/b34ea31fe013569d42b7e8681ef3f717f77c5b72CVE reference, Linux
Products and packages named in the record
CWE details
CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.