CVE-2021-47372

Kernel crash via freed MACB clock access

Published May 21, 2024 · Updated May 11, 2026

Use-after-free in the MACB PCI driver in Linux 4.10 through 5.14.8 allows local users to crash the kernel during module removal. macb_remove calls platform_device_unregister before using pclk and hclk pointers stored in the released platform data. Reaching this path requires the macb_pci module and privileges to unload it; the stale clock access can corrupt kernel memory and interrupt the host.

CVSS severity7.8
High
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

Use-after-free in the MACB PCI driver in Linux 4.10 through 5.14.8 allows local users to crash the kernel during module removal. macb_remove calls platform_device_unregister before using pclk and hclk pointers stored in the released platform data. Reaching this path requires the macb_pci module and privileges to unload it; the stale clock access can corrupt kernel memory and interrupt the host.

The record

CVE
CVE-2021-47372
Published
May 21, 2024
Updated
May 11, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
CWE-416, T1499.004
Attack vector
local
Privileges
admin

Timeline

How it unfolded

  1. May 21, 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=4.10
  2. Affected versionversion=83a77e9ec4150ee4acc635638f7dedd9da523a26 <1da750d1e2140ef43d64d17f301ff6f41b45541e
  3. Affected versionversion=83a77e9ec4150ee4acc635638f7dedd9da523a26 <46670fb832ee80943715df618632ca13c2e96f2b
  4. Affected versionversion=83a77e9ec4150ee4acc635638f7dedd9da523a26 <4ad6f2d23b0f6ac0d3e5f3102a4256d1c86c90f5
  5. Affected versionversion=83a77e9ec4150ee4acc635638f7dedd9da523a26 <7721221e87d25c9840d9ca6b986dbdc410d5ce2b
  6. Affected versionversion=83a77e9ec4150ee4acc635638f7dedd9da523a26 <a7d521cc726f30b8e679a6f36d04b18a8ab3c536
  7. Affected versionversion=83a77e9ec4150ee4acc635638f7dedd9da523a26 <d82d5303c4c539db86588ffb5dc5b26c3f1513e8

What conditions does exploitation require?

Attack vectorlocal
Required privilegesadmin

What is affected?

The Linux Kernel Organization · Linuxversion=4.10; version=83a77e9ec4150ee4acc635638f7dedd9da523a26 <1da750d1e2140ef43d64d17f301ff6f41b45541e; version=83a77e9ec4150ee4acc635638f7dedd9da523a26 <46670fb832ee80943715df618632ca13c2e96f2b; version=83a77e9ec4150ee4acc635638f7dedd9da523a26 <4ad6f2d23b0f6ac0d3e5f3102a4256d1c86c90f5; version=83a77e9ec4150ee4acc635638f7dedd9da523a26 <7721221e87d25c9840d9ca6b986dbdc410d5ce2b; version=83a77e9ec4150ee4acc635638f7dedd9da523a26 <a7d521cc726f30b8e679a6f36d04b18a8ab3c536; version=83a77e9ec4150ee4acc635638f7dedd9da523a26 <d82d5303c4c539db86588ffb5dc5b26c3f1513e8

Published CVSS scores

7.8CanonicalCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/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
Privilegesadmin
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-416Use After Free
T1499.004Application 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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