CVE-2021-47502

Service interruption via duplicate channel-list insertion

Published May 24, 2024 · Updated Aug 5, 2026

Kernel list corruption in the wcd934x ASoC codec in Linux 5.6 and later affected branches allows local users to interrupt service. The channel-mapping paths insert a channel node into multiple DAI lists without first verifying that the node is free and can delete a node that is not on the selected list. Exploitation requires a system with WCD934x audio hardware and local access to exercise nontrivial ALSA channel mappings, corrupting kernel list state with availability-only impact.

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

Kernel list corruption in the wcd934x ASoC codec in Linux 5.6 and later affected branches allows local users to interrupt service. The channel-mapping paths insert a channel node into multiple DAI lists without first verifying that the node is free and can delete a node that is not on the selected list. Exploitation requires a system with WCD934x audio hardware and local access to exercise nontrivial ALSA channel mappings, corrupting kernel list state with availability-only impact.

The record

CVE
CVE-2021-47502
Published
May 24, 2024
Updated
Aug 5, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
T1499
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. May 24, 2024CVE publishedPublication date reported by the CVE source.
  2. Aug 5, 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=5.6
  2. Affected versionversion=dd9eb19b567303e4b92747dcfb5deedb182af111 <1089dac26c6b4b833323ae6c0ceab29fb30ede72
  3. Affected versionversion=dd9eb19b567303e4b92747dcfb5deedb182af111 <23ba28616d3063bd4c4953598ed5e439ca891101
  4. Affected versionversion=dd9eb19b567303e4b92747dcfb5deedb182af111 <339ffb5b56005582aacc860524d2d208604049d1

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=5.6; version=dd9eb19b567303e4b92747dcfb5deedb182af111 <1089dac26c6b4b833323ae6c0ceab29fb30ede72; version=dd9eb19b567303e4b92747dcfb5deedb182af111 <23ba28616d3063bd4c4953598ed5e439ca891101; version=dd9eb19b567303e4b92747dcfb5deedb182af111 <339ffb5b56005582aacc860524d2d208604049d1

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

T1499Endpoint Denial of Service

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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