CVE-2021-47171

Service interruption via failed USB adapter binding

Published Mar 25, 2024 · Updated May 11, 2026

A memory leak in affected Linux kernels allows local users to exhaust kernel memory by repeatedly triggering failed SMSC75xx USB adapter binding. In drivers/net/usb/smsc75xx.c, smsc75xx_bind allocates private adapter data but returns directly after readiness or reset errors without freeing it. Reachability requires the SMSC75xx USB driver and error-producing adapter initialization; each failed bind leaks kernel memory, so repetition can interrupt service.

CVSS severity5.5
Medium
EPSS probability0.24%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

A memory leak in affected Linux kernels allows local users to exhaust kernel memory by repeatedly triggering failed SMSC75xx USB adapter binding. In drivers/net/usb/smsc75xx.c, smsc75xx_bind allocates private adapter data but returns directly after readiness or reset errors without freeing it. Reachability requires the SMSC75xx USB driver and error-producing adapter initialization; each failed bind leaks kernel memory, so repetition can interrupt service.

The record

CVE
CVE-2021-47171
Published
Mar 25, 2024
Updated
May 11, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
CWE-401, T1499
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Mar 25, 2024CVE publishedPublication date reported by the CVE source.
  2. May 11, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=2.6.34
  2. Affected versionversion=d0cad871703b898a442e4049c532ec39168e5b57 <200dbfcad8011e50c3cec269ed7b980836eeb1fa
  3. Affected versionversion=d0cad871703b898a442e4049c532ec39168e5b57 <22c840596af0c09068b6cf948616e6496e59e07f
  4. Affected versionversion=d0cad871703b898a442e4049c532ec39168e5b57 <46a8b29c6306d8bbfd92b614ef65a47c900d8e70
  5. Affected versionversion=d0cad871703b898a442e4049c532ec39168e5b57 <635ac38b36255d3cfb8312cf7c471334f4d537e0
  6. Affected versionversion=d0cad871703b898a442e4049c532ec39168e5b57 <70c886ac93f87ae7214a0c69151a28a8075dd95b
  7. Affected versionversion=d0cad871703b898a442e4049c532ec39168e5b57 <9e6a3eccb28779710cbbafc4f4258d92509c6d07
  8. Affected versionversion=d0cad871703b898a442e4049c532ec39168e5b57 <9e6b8c1ff9d997e1fa16cbd2d60739adf6dc1bbc
  9. Affected versionversion=d0cad871703b898a442e4049c532ec39168e5b57 <b95fb96e6339e34694dd578fb6bde3575b01af17

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=2.6.34; version=d0cad871703b898a442e4049c532ec39168e5b57 <200dbfcad8011e50c3cec269ed7b980836eeb1fa; version=d0cad871703b898a442e4049c532ec39168e5b57 <22c840596af0c09068b6cf948616e6496e59e07f; version=d0cad871703b898a442e4049c532ec39168e5b57 <46a8b29c6306d8bbfd92b614ef65a47c900d8e70; version=d0cad871703b898a442e4049c532ec39168e5b57 <635ac38b36255d3cfb8312cf7c471334f4d537e0; version=d0cad871703b898a442e4049c532ec39168e5b57 <70c886ac93f87ae7214a0c69151a28a8075dd95b; version=d0cad871703b898a442e4049c532ec39168e5b57 <9e6a3eccb28779710cbbafc4f4258d92509c6d07; version=d0cad871703b898a442e4049c532ec39168e5b57 <9e6b8c1ff9d997e1fa16cbd2d60739adf6dc1bbc; version=d0cad871703b898a442e4049c532ec39168e5b57 <b95fb96e6339e34694dd578fb6bde3575b01af17

Published CVSS scores

5.5NIST NVDCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-401Missing Release of Memory after Effective Lifetime
T1499Endpoint Denial of Service

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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