Security readout for executives and security teams
Plain-English summary
CVE-2021-47386 is a Linux kernel bug in the w83791d hardware-monitoring driver. A local authenticated user could potentially trigger a NULL pointer dereference through specific device-read conditions, causing kernel impact. The published CVSS score is high, but exposure is narrower than a remote internet-facing issue.
Executive priority
Treat as high priority for Linux fleet patching, especially shared servers and systems where local users or workloads are less trusted. It is not evidenced as actively exploited in the provided sources.
Technical view
The issue is CWE-476 in the Linux kernel hwmon w83791d driver. The fix removes the obsolete lm75[] structure field after use of devm_i2c_new_dummy_device(). The CVSS vector is AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H. Stable kernel commits are referenced as fixes.
Likely exposure
Exposure appears limited to Linux systems running affected kernel versions with the w83791d hwmon driver path relevant. The CVSS vector requires local privileges, so typical exposure is post-access local escalation or kernel disruption risk, not direct remote exploitation.
Exploitation context
The provided sources do not show CISA KEV listing or active exploitation. The condition depends on driver-read values meeting a specific bit pattern. No public exploit status is provided in the source bundle.
Researcher notes
The record ties the issue to a NULL pointer dereference in w83791d and references four stable commits. Evidence is incomplete on exact downstream distro package mapping, exploit availability, and real-world hardware prevalence.
Mitigation direction
- Update affected Linux kernels to versions containing the referenced stable fixes.
- Prioritize vendor or distribution kernel advisories for exact package versions.
- Check whether systems load or require the w83791d hwmon driver.
- If patching is delayed, consult vendor guidance for temporary controls.
Validation and detection
- Inventory Linux kernel versions across servers, appliances, and images.
- Check loaded kernel modules and hardware-monitoring driver usage.
- Confirm vendor kernel packages include the referenced stable commits.
- Track remediation through vulnerability scans and package baseline checks.
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
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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CWE-476: Exact CWE lookup
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Open ATT&CK lookupCVE-2021-47386 mapping review
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Open ATT&CK lookup- Severity
- High
- CVSS
- 7.8 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
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
CVSS vector scores
1 official scoreWe collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H1.85.9CISA-ADPVulnerability scoring details
Base CVSS 3.1 score
7.8HighVector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
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/44d3c480e4e2a75bf6296a18b4356157991ccd80CVE reference, Linux
- https://git.kernel.org/stable/c/516d9055039017a20a698103be2b556b4c976bb8CVE reference, Linux
- https://git.kernel.org/stable/c/16887ae4e3defd2c4e7913b6c539f33eaf4eac5cCVE reference, Linux
- https://git.kernel.org/stable/c/943c15ac1b84d378da26bba41c83c67e16499ac4CVE 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.