CVE-2021-47467

Memory consumption via leaked KUnit resource references

Published May 22, 2024 · Updated May 11, 2026

Reference-count leakage in KUnit in Linux 5.14 through 5.14.14 allows attackers to consume kernel memory during test execution. The kfree_at_end helper calls kunit_alloc_and_get_resource but discards the returned object after that call increments its reference count, leaving the reference unreleased. Reachability requires execution of the affected KUnit executor test; published sources do not demonstrate impact on ordinary kernel workloads.

CVSS severity5.3
Medium
EPSS probability0.49%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Reference-count leakage in KUnit in Linux 5.14 through 5.14.14 allows attackers to consume kernel memory during test execution. The kfree_at_end helper calls kunit_alloc_and_get_resource but discards the returned object after that call increments its reference count, leaving the reference unreleased. Reachability requires execution of the affected KUnit executor test; published sources do not demonstrate impact on ordinary kernel workloads.

The record

CVE
CVE-2021-47467
Published
May 22, 2024
Updated
May 11, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
T1499
Attack vector
Unavailable
Privileges
Unavailable

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=1d71307a6f94df3750f8f884545a769e227172fe <bbdd158b40b66a9403391a517f24ef6613573446
  2. Affected versionversion=1d71307a6f94df3750f8f884545a769e227172fe <f62314b1ced25c58b86e044fc951cd6a1ea234cf
  3. Affected versionversion=5.14

What conditions does exploitation require?

Attack vectorUnavailable in this record.
Required privilegesUnavailable in this record.

What is affected?

The Linux Kernel Organization · Linuxversion=1d71307a6f94df3750f8f884545a769e227172fe <bbdd158b40b66a9403391a517f24ef6613573446; version=1d71307a6f94df3750f8f884545a769e227172fe <f62314b1ced25c58b86e044fc951cd6a1ea234cf; version=5.14

Published CVSS scores

5.3CISA-ADPCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L

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)
VectorUnavailable
PrivilegesUnavailable
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

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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