CVE-2021-47464

Kernel panic via null audit context write

Published May 22, 2024 · Updated May 11, 2026

NULL pointer dereference in the audit subsystem in Linux Kernel 5.3 through 5.14.14 allows local users to trigger a kernel panic. audit_filter_rules duplicates a matching rule filter key through ctx even when audit_filter_task passes ctx as NULL. A keyed task audit rule must match, and triggering it can interrupt the host by panicking the kernel.

CVSS severity7.4
High
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

NULL pointer dereference in the audit subsystem in Linux Kernel 5.3 through 5.14.14 allows local users to trigger a kernel panic. audit_filter_rules duplicates a matching rule filter key through ctx even when audit_filter_task passes ctx as NULL. A keyed task audit rule must match, and triggering it can interrupt the host by panicking the kernel.

The record

CVE
CVE-2021-47464
Published
May 22, 2024
Updated
May 11, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
CWE-476, T1499
Attack vector
local
Privileges
unauthenticated

Timeline

How it unfolded

  1. May 22, 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=5.3
  2. Affected versionversion=bf361231c295d92a28ca283ea713f56e93e55796 <16802fa4c33eb1a8efb23f1e93365190e4047d05
  3. Affected versionversion=bf361231c295d92a28ca283ea713f56e93e55796 <4e9e46a700201b4c85081fd478c99c692a9aaa0d
  4. Affected versionversion=bf361231c295d92a28ca283ea713f56e93e55796 <6e3ee990c90494561921c756481d0e2125d8b895
  5. Affected versionversion=bf361231c295d92a28ca283ea713f56e93e55796 <d6f451f1f60c58d73038c7c3177066f8f084e2a2

What conditions does exploitation require?

Attack vectorlocal
Required privilegesunauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=5.3; version=bf361231c295d92a28ca283ea713f56e93e55796 <16802fa4c33eb1a8efb23f1e93365190e4047d05; version=bf361231c295d92a28ca283ea713f56e93e55796 <4e9e46a700201b4c85081fd478c99c692a9aaa0d; version=bf361231c295d92a28ca283ea713f56e93e55796 <6e3ee990c90494561921c756481d0e2125d8b895; version=bf361231c295d92a28ca283ea713f56e93e55796 <d6f451f1f60c58d73038c7c3177066f8f084e2a2
The Linux Kernel Organization · Linux Kernelversion=5.3; version=bf361231c295 <16802fa4c33e; version=bf361231c295 <4e9e46a70020; version=bf361231c295 <6e3ee990c904; version=bf361231c295 <d6f451f1f60c

Published CVSS scores

7.4CISA-ADPCVSS:3.1/AV:L/AC:H/PR:N/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
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-476NULL Pointer Dereference
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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