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CVE Record

CVE-2021-47121: net: caif: fix memory leak in cfusbl_device_notify

In the Linux kernel, the following vulnerability has been resolved: net: caif: fix memory leak in cfusbl_device_notify In case of caif_enroll_dev() fail, allocated link_support won't be assigned to the corresponding structure. So simply free allocated pointer in case of error.

UnknownCVSS not scoredNot KEV-listedUpdated
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Glexia's TakeAutomated analysisunknown

Security readout for executives and security teams

Plain-English summary

This is a Linux kernel memory leak in the CAIF networking USB device notification path. If device enrollment fails, allocated memory was not freed. The provided sources do not show data theft, privilege escalation, remote attack, or active exploitation.

Executive priority

Treat as routine kernel hygiene unless affected CAIF-capable systems are exposed to untrusted device events or cannot be updated. There is no source-backed evidence of exploitation, but stale kernels should still be remediated.

Technical view

CVE-2021-47121 fixes a leak in net/caif cfusbl_device_notify(): when caif_enroll_dev() fails, link_support is allocated but not attached to the target structure, so it must be freed on the error path.

Likely exposure

Exposure appears limited to Linux systems running affected kernel versions where the CAIF USB-related code path is present and reachable. The source bundle lists Linux kernel versions including 3.3 through 5.13-era stable lines, but gives no CPEs.

Exploitation context

The provided evidence does not show active exploitation, public exploit use, or KEV listing. Impact is described only as a memory leak on an error path, so operational risk depends on whether the code path can be triggered in the environment.

Researcher notes

The CVE record lacks CVSS, CWE, CPEs, and detailed trigger conditions. Analysis should focus on kernel branch mapping, distribution backports, and whether cfusbl_device_notify and caif_enroll_dev are reachable in deployed configurations.

Mitigation direction

  • Update affected Linux kernels to vendor-supported fixed releases.
  • Review the referenced stable kernel commits for the applicable branch.
  • Check distribution advisories for packaged kernel backports.
  • If unsure, ask the OS vendor whether CAIF fixes are included.

Validation and detection

  • Inventory Linux kernel versions across servers, appliances, and embedded systems.
  • Check whether affected systems include or enable CAIF USB-related kernel support.
  • Confirm installed kernel packages include the referenced upstream fix or vendor backport.
  • Document systems that cannot be upgraded and track vendor remediation.
Prepared
Confidence
medium
Sources
10

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-2021-47121 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
9Source 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
LinuxLinux7ad65bf68d705b445ef10b77ab50dab22be185ee, 7ad65bf68d705b445ef10b77ab50dab22be185ee, 7ad65bf68d705b445ef10b77ab50dab22be185ee, 7ad65bf68d705b445ef10b77ab50dab22be185ee, 7ad65bf68d705b445ef10b77ab50dab22be185ee, 7ad65bf68d705b445ef10b77ab50dab22be185ee, 7ad65bf68d705b445ef10b77ab50dab22be185ee, 7ad65bf68d705b445ef10b77ab50dab22be185eeunaffected
LinuxLinux3.3, 0, 4.4.272, 4.9.272, 4.14.236, 4.19.194, 5.4.125, 5.10.43, 5.12.10, 5.13affected
Weakness

CWE details

No CWE listed

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