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CVE Record

CVE-2021-47032: mt76: mt7915: fix tx skb dma unmap

In the Linux kernel, the following vulnerability has been resolved: mt76: mt7915: fix tx skb dma unmap The first pointer in the txp needs to be unmapped as well, otherwise it will leak DMA mapping entries

UnknownCVSS not scoredNot KEV-listedUpdated
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Glexia's TakeAutomated analysisunknown

Security readout for executives and security teams

Plain-English summary

This Linux kernel issue is a resource leak in the mt76/mt7915 wireless driver. A transmit buffer DMA mapping was not fully released, which could gradually consume DMA mapping entries. Business impact is most relevant to Linux systems using the MediaTek MT7915 Wi-Fi driver, where reliability could degrade.

Executive priority

Treat as a targeted kernel maintenance item, not an emergency based on current evidence. Raise priority for routers, appliances, or Linux endpoints that rely on MT7915 Wi-Fi and cannot tolerate wireless or kernel stability issues.

Technical view

The fix unmapped the first pointer in the txp structure during mt7915 transmit skb cleanup. Without that unmap, DMA mapping entries leak. The CVE record lists Linux kernel versions including 5.10, 5.10.37, 5.11.21, 5.12.4, and 5.13 as affected, with stable kernel commits referenced as fixes.

Likely exposure

Exposure appears limited to Linux systems running affected kernels with the mt76 mt7915 driver active, typically devices using MediaTek MT7915 wireless hardware. Systems without this driver or hardware are unlikely to be exposed based on the provided sources.

Exploitation context

The provided sources do not report active exploitation, public exploit code, KEV listing, CVSS, or CWE data. The described failure mode is a kernel driver DMA resource leak, suggesting reliability risk rather than confirmed remote code execution.

Researcher notes

Evidence is narrow: the source text identifies a missing DMA unmap in mt7915 tx skb handling and links kernel stable commits. It does not provide exploitability analysis, attack prerequisites, CVSS scoring, or a named mitigation beyond applying fixed kernel code.

Mitigation direction

  • Update to a Linux kernel build containing the referenced stable fixes.
  • Check distribution or appliance vendor advisories for backported kernel packages.
  • Prioritize systems using MediaTek MT7915 Wi-Fi hardware or mt76 modules.
  • Schedule remediation with normal kernel reboot and rollback planning.

Validation and detection

  • Inventory kernel versions on systems using MediaTek MT7915 wireless hardware.
  • Confirm whether the mt76 and mt7915 driver modules are loaded.
  • Verify vendor kernel packages include one of the referenced stable fixes.
  • Monitor affected systems for network instability or resource exhaustion symptoms.
Prepared
Confidence
medium
Sources
6

Public sources used

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.

Potential ATT&CK relevance

Conservative CVE-to-ATT&CK context

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ATT&CK lookup starting points

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CVE-2021-47032 mapping review

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Vulnerability profileCVE Program record
Severity
Unknown
CVSS
Not scored
Known Exploited
No
Published
Official CVE source material

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.

0CVSS vectors
3Timeline events
2ADP providers
5Source links

SSVC decision data

CISA-ADPCISA Coordinator
Timestamp
Version
2.0.3
Exploitation: noneAutomatable: noTechnical Impact: partial

Vulnerability timeline

Timeline events are normalized from CVE metadata, CNA source timelines, ADP timelines, and KEV metadata when present.

  1. CVE reservedCVE Program

    The CVE ID was reserved by the assigning CNA.

  2. CVE publishedCVE Program

    The CVE record was published.

  3. CVE updatedCVE Program

    The CVE record metadata indicates this as the latest update time.

ADP provider summaries

CVECVE Program Container
CISA-ADPCISA ADP Vulnrichment
other:ssvc

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
LinuxLinux27d5c528a7ca08dcd44877fdd9fc08b76630bf77, 27d5c528a7ca08dcd44877fdd9fc08b76630bf77, 27d5c528a7ca08dcd44877fdd9fc08b76630bf77, 27d5c528a7ca08dcd44877fdd9fc08b76630bf77unaffected
LinuxLinux5.10, 0, 5.10.37, 5.11.21, 5.12.4, 5.13affected
Weakness

CWE details

No CWE listed

CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.