CVE-2021-47143

Local service interruption via stale SMCD list entry

Published Mar 25, 2024 · Updated May 11, 2026

Incomplete cleanup in the Linux kernel allows local users to interrupt service through a failed SMCD device registration. The smcd_register_dev() path links the device into smcd_dev_list before device_add(), then leaves that entry linked if registration fails and the device is freed. NVD rates the path as local and low-privileged, but public sources do not document how a local user can force the required failure.

CVSS severity5.5
Medium
EPSS probability0.22%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
Coverage for this vulnerability

See if you're affected

Explore vulnerability checks for your environment with Hinoki.

Book a demo

Summary

What happened

Incomplete cleanup in the Linux kernel allows local users to interrupt service through a failed SMCD device registration. The smcd_register_dev() path links the device into smcd_dev_list before device_add(), then leaves that entry linked if registration fails and the device is freed. NVD rates the path as local and low-privileged, but public sources do not document how a local user can force the required failure.

The record

CVE
CVE-2021-47143
Published
Mar 25, 2024
Updated
May 11, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
CWE-459, 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

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

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

  1. Affected versionversion=4.19
  2. Affected versionversion=c6ba7c9ba43de1b57e9a53946e7ff988554c84ed <40588782f1016c655ae1d302892f61d35af96842
  3. Affected versionversion=c6ba7c9ba43de1b57e9a53946e7ff988554c84ed <444d7be9532dcfda8e0385226c862fd7e986f607
  4. Affected versionversion=c6ba7c9ba43de1b57e9a53946e7ff988554c84ed <8b2cdc004d21a7255f219706dca64411108f7897

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=4.19; version=c6ba7c9ba43de1b57e9a53946e7ff988554c84ed <40588782f1016c655ae1d302892f61d35af96842; version=c6ba7c9ba43de1b57e9a53946e7ff988554c84ed <444d7be9532dcfda8e0385226c862fd7e986f607; version=c6ba7c9ba43de1b57e9a53946e7ff988554c84ed <8b2cdc004d21a7255f219706dca64411108f7897

Published CVSS scores

5.5NIST National Vulnerability DatabaseCVSS: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

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

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-459Incomplete Cleanup
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

See the directory against your own environment.

Your stack

Check the software in your environment

Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.

Book a demo