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CVE Record

CVE-2021-46979: iio: core: fix ioctl handlers removal

In the Linux kernel, the following vulnerability has been resolved: iio: core: fix ioctl handlers removal Currently ioctl handlers are removed twice. For the first time during iio_device_unregister() then later on inside iio_device_unregister_eventset() and iio_buffers_free_sysfs_and_mask(). Double free leads to kernel panic. Fix this by not touching ioctl handlers list directly but rather letting code responsible for registration call the matching cleanup routine itself.

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 cause a system crash when certain Industrial I/O cleanup paths remove ioctl handlers twice. The business impact is primarily availability risk: affected systems could panic instead of continuing service. The source bundle does not show active exploitation, remote reachability, or a CVSS score.

Executive priority

Handle through normal kernel maintenance unless affected systems are safety-critical, embedded, or high-availability. Escalate if vendor guidance confirms reachable local denial of service in deployed configurations.

Technical view

CVE-2021-46979 is a Linux kernel IIO core double-free flaw. ioctl handlers were removed during iio_device_unregister(), then removed again during eventset or buffer cleanup. The documented outcome is kernel panic. Stable kernel commits change cleanup ownership so registration paths call matching cleanup routines.

Likely exposure

Exposure is limited to Linux kernels in the affected source range, especially systems using IIO drivers or related device cleanup paths. Downstream distributions may have backported fixes, so version strings alone are not enough to determine exposure.

Exploitation context

The provided sources do not identify public exploitation, KEV listing, exploit maturity, attack vector, or required privileges. Treat this as a kernel availability vulnerability until vendor-specific advisories provide clearer reachability details.

Researcher notes

Key uncertainty is reachability. The CVE text confirms a double removal and kernel panic, but not triggering conditions, privilege requirements, or affected drivers. Validate against exact kernel trees and downstream patches rather than relying only on upstream version labels.

Mitigation direction

  • Identify Linux kernel versions across affected servers, appliances, and embedded systems.
  • Check vendor or distribution advisories for CVE-2021-46979 backport status.
  • Update to a supported kernel containing the referenced stable fixes.
  • Prioritize systems using IIO drivers or exposed to untrusted local workloads.
  • Monitor for unexpected kernel panics on affected kernel branches.

Validation and detection

  • Map running kernel builds to vendor advisories and changelogs for this CVE.
  • Confirm whether the referenced stable commits are present or backported.
  • Review whether IIO drivers are enabled or loaded on relevant systems.
  • Check incident logs for kernel panic patterns around IIO unregister paths.
  • Document unresolved systems where vendor fix status is unclear.
Prepared
Confidence
medium
Sources
5

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-2021-46979 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
4Source 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
LinuxLinux8dedcc3eee3aceb37832176f0a1b03d5687acda3, 8dedcc3eee3aceb37832176f0a1b03d5687acda3, 8dedcc3eee3aceb37832176f0a1b03d5687acda3unaffected
LinuxLinux5.11, 0, 5.11.22, 5.12.5, 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.