CVE-2021-47020

Service interruption via SoundWire runtime memory leak

Published Feb 29, 2024 · Updated May 11, 2026

Memory leak in the Linux SoundWire stream subsystem allows local users to exhaust memory by triggering a stream-configuration failure. The error path allocates a slave runtime but has not linked it into slave_rt_list when master-runtime cleanup runs, so the allocation remains unreleased. Reachability requires local low-privileged access and a SoundWire configuration failure; repeated failures can deplete memory and interrupt service.

CVSS severity5.5
Medium
EPSS probability0.23%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Memory leak in the Linux SoundWire stream subsystem allows local users to exhaust memory by triggering a stream-configuration failure. The error path allocates a slave runtime but has not linked it into slave_rt_list when master-runtime cleanup runs, so the allocation remains unreleased. Reachability requires local low-privileged access and a SoundWire configuration failure; repeated failures can deplete memory and interrupt service.

The record

CVE
CVE-2021-47020
Published
Feb 29, 2024
Updated
May 11, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
CWE-401, T1499.004
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Feb 29, 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=4.18
  2. Affected versionversion=89e590535f32d4bc548bcf266f3b046e50942f6d <2f17ac005b320c85d686088cfd4c2e7017912b88
  3. Affected versionversion=89e590535f32d4bc548bcf266f3b046e50942f6d <342260fe821047c3d515e3d28085d73fbdce3e80
  4. Affected versionversion=89e590535f32d4bc548bcf266f3b046e50942f6d <48f17f96a81763c7c8bf5500460a359b9939359f
  5. Affected versionversion=89e590535f32d4bc548bcf266f3b046e50942f6d <7c468deae306d0cbbd539408c26cfec04c66159a
  6. Affected versionversion=89e590535f32d4bc548bcf266f3b046e50942f6d <870533403ffa28ff63e173045fc5369365642002
  7. Affected versionversion=89e590535f32d4bc548bcf266f3b046e50942f6d <effd2bd62b416f6629e18e3ce077c60de14cfdea

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=4.18; version=89e590535f32d4bc548bcf266f3b046e50942f6d <2f17ac005b320c85d686088cfd4c2e7017912b88; version=89e590535f32d4bc548bcf266f3b046e50942f6d <342260fe821047c3d515e3d28085d73fbdce3e80; version=89e590535f32d4bc548bcf266f3b046e50942f6d <48f17f96a81763c7c8bf5500460a359b9939359f; version=89e590535f32d4bc548bcf266f3b046e50942f6d <7c468deae306d0cbbd539408c26cfec04c66159a; version=89e590535f32d4bc548bcf266f3b046e50942f6d <870533403ffa28ff63e173045fc5369365642002; version=89e590535f32d4bc548bcf266f3b046e50942f6d <effd2bd62b416f6629e18e3ce077c60de14cfdea

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

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

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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
T1499.004Endpoint Denial of Service: Application or System Exploitation

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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