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CVE Record

CVE-2021-47385: hwmon: (w83792d) Fix NULL pointer dereference by removing unnecessary structure field

In the Linux kernel, the following vulnerability has been resolved: hwmon: (w83792d) Fix NULL pointer dereference by removing unnecessary structure field If driver read val value sufficient for (val & 0x08) && (!(val & 0x80)) && ((val & 0x7) == ((val >> 4) & 0x7)) from device then Null pointer dereference occurs. (It is possible if tmp = 0b0xyz1xyz, where same literals mean same numbers) Also lm75[] does not serve a purpose anymore after switching to devm_i2c_new_dummy_device() in w83791d_detect_subclients(). The patch fixes possible NULL pointer dereference by removing lm75[]. Found by Linux Driver Verification project (linuxtesting.org). [groeck: Dropped unnecessary continuation lines, fixed multipline alignment]

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 can crash kernel code in a hardware monitoring driver when a device returns a specific value pattern. The available record does not provide CVSS, observed exploitation, or broad impact details. Business urgency depends on whether affected Linux kernels actually load or use the w83792d hardware monitoring driver.

Executive priority

Track this as a targeted kernel maintenance item, not an emergency based on current evidence. Prioritize remediation for affected Linux fleets using hardware monitoring drivers, especially where uptime and host stability are important.

Technical view

CVE-2021-47385 is a NULL pointer dereference in the Linux hwmon w83792d driver. The record says certain device-read values can trigger the dereference. The upstream fix removes an obsolete lm75[] field after devm_i2c_new_dummy_device() usage. Affected Linux versions are listed around 5.4 through 5.15, with stable kernel commits referenced.

Likely exposure

Exposure is most likely on Linux systems running affected kernel versions where the w83792d hwmon driver is present and interacts with relevant hardware. Systems without this driver or hardware path appear less likely exposed, but the source bundle does not define complete product or distribution mappings.

Exploitation context

The source bundle does not report active exploitation, public exploit use, or KEV listing. The trigger depends on a specific value read from a device by the driver. Treat this primarily as a potential kernel denial-of-service or stability risk unless vendor advisories state broader impact.

Researcher notes

Evidence is limited to the CVE description and Linux stable commit references. No CVSS, CWE, exploit status, or distribution-specific fixed package data is provided. Validation should focus on driver reachability, kernel branch mapping, and whether vendor kernels backported the patch.

Mitigation direction

  • Apply vendor Linux kernel updates containing the referenced stable fixes.
  • Check distribution advisories for backported fixes for CVE-2021-47385.
  • Prioritize systems using hardware monitoring and affected kernel branches.
  • If updates are delayed, ask the vendor about safe driver-specific workarounds.

Validation and detection

  • Inventory Linux kernel versions against vendor CVE-2021-47385 advisories.
  • Confirm whether the w83792d hwmon driver is installed or loaded.
  • Verify patched kernels include the relevant stable commit or vendor backport.
  • Review system hardware monitoring dependencies before changing driver availability.
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

These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.

ATT&CK lookup starting points

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CVE-2021-47385 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

CISA-ADPCISA ADP Vulnrichment
other:ssvc
CVECVE Program Container

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
LinuxLinuxf64211151db4269341ee6432ce832ae3756725ad, f64211151db4269341ee6432ce832ae3756725ad, f64211151db4269341ee6432ce832ae3756725ad, f64211151db4269341ee6432ce832ae3756725adunaffected
LinuxLinux5.4, 0, 5.4.151, 5.10.71, 5.14.10, 5.15affected
Weakness

CWE details

No CWE listed

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