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CVE Record

CVE-2021-47405: HID: usbhid: free raw_report buffers in usbhid_stop

In the Linux kernel, the following vulnerability has been resolved: HID: usbhid: free raw_report buffers in usbhid_stop Free the unsent raw_report buffers when the device is removed. Fixes a memory leak reported by syzbot at: https://syzkaller.appspot.com/bug?id=7b4fa7cb1a7c2d3342a2a8a6c53371c8c418ab47

UnknownCVSS not scoredNot KEV-listedUpdated
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Glexia's TakeAutomated analysislow

Security readout for executives and security teams

Plain-English summary

This Linux kernel flaw is a memory leak in USB HID handling when a device is removed. The sources do not show active exploitation or a CVSS score. Business urgency is generally lower than remote code execution, but exposed systems should still receive normal kernel maintenance updates.

Executive priority

Handle through routine kernel patch management unless USB HID attachment is exposed to untrusted users. There is no source-backed evidence of active exploitation, but memory leaks can still affect reliability on exposed systems.

Technical view

The usbhid_stop path did not free unsent raw_report buffers during USB HID device removal. The Linux stable fixes free those buffers. Evidence identifies affected Linux kernel ranges and stable commit references, but provides no CVSS vector, CWE, exploit details, or operational workaround beyond fixed kernel code.

Likely exposure

Likely exposure is Linux systems running affected kernels with USB HID support. Practical risk appears most relevant where untrusted users or virtualized workloads can attach or remove HID devices. Network-only exposure is not indicated by the supplied sources.

Exploitation context

The bundle cites a syzbot-reported memory leak and states KEV is false. No supplied source reports active exploitation, public weaponization, privilege impact, or remote attack path. Treat exploitability evidence as incomplete.

Researcher notes

The key artifact is a cleanup bug in HID usbhid raw_report buffer handling on device teardown. The supplied record lacks CVSS, CWE, and detailed affected-version boundaries beyond Linux kernel version data and stable patch references.

Mitigation direction

  • Update to a vendor kernel containing the referenced stable fixes.
  • Prioritize endpoints, kiosks, labs, and virtual hosts with USB passthrough.
  • Restrict untrusted physical or virtual USB HID device access where practical.
  • Check Linux vendor advisories for package-specific fixed versions.

Validation and detection

  • Inventory Linux kernel versions across managed systems.
  • Confirm installed kernels include the relevant stable fix commit for their branch.
  • Review exposure to USB HID attachment or passthrough by untrusted users.
  • Monitor for unusual memory pressure around repeated USB HID removal events.
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-2021-47405 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

CVECVE Program Container
CISA-ADPCISA ADP Vulnrichment
other:ssvc

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
LinuxLinuxf129ea6d1efe0eddcbb1f0faaec5623788ad9e58, f129ea6d1efe0eddcbb1f0faaec5623788ad9e58, f129ea6d1efe0eddcbb1f0faaec5623788ad9e58, f129ea6d1efe0eddcbb1f0faaec5623788ad9e58, f129ea6d1efe0eddcbb1f0faaec5623788ad9e58, f129ea6d1efe0eddcbb1f0faaec5623788ad9e58, f129ea6d1efe0eddcbb1f0faaec5623788ad9e58, f129ea6d1efe0eddcbb1f0faaec5623788ad9e58unaffected
LinuxLinux2.6.28, 0, 4.4.286, 4.9.285, 4.14.249, 4.19.209, 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.