CVE-2021-47023

Kernel crash via premature delayed-work cancellation

Published Feb 28, 2024 · Updated May 11, 2026

A race in Linux kernel 5.10 through 5.10.36, 5.11 through 5.11.20, and 5.12 through 5.12.3 allows attackers to crash the kernel. During Prestera port creation, prestera_port_handle_event calls cancel_delayed_work for an initial down event even when the prior port state was not up and running. The path requires Marvell Prestera hardware and concurrent firmware event handling; the upstream record does not identify the underlying cause of the invalid work-state access.

CVSS severity8.2
High
EPSS probability0.84%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

A race in Linux kernel 5.10 through 5.10.36, 5.11 through 5.11.20, and 5.12 through 5.12.3 allows attackers to crash the kernel. During Prestera port creation, prestera_port_handle_event calls cancel_delayed_work for an initial down event even when the prior port state was not up and running. The path requires Marvell Prestera hardware and concurrent firmware event handling; the upstream record does not identify the underlying cause of the invalid work-state access.

The record

CVE
CVE-2021-47023
Published
Feb 28, 2024
Updated
May 11, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
Unavailable
Attack vector
Unavailable
Privileges
Unavailable

Timeline

How it unfolded

  1. Feb 28, 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=501ef3066c89d7f9045315e1be58749cf9e6814d <0ce6052802be2cb61a57b753e41301339c88c839
  2. Affected versionversion=501ef3066c89d7f9045315e1be58749cf9e6814d <333980481b99edb24ebd5d1a53af70a15d9146de
  3. Affected versionversion=501ef3066c89d7f9045315e1be58749cf9e6814d <9d1ba11fabdd8f25abb24272ef1621417981320b
  4. Affected versionversion=501ef3066c89d7f9045315e1be58749cf9e6814d <b5bba6ede42693f50ce1c9944315cefed7491061
  5. Affected versionversion=5.10

What conditions does exploitation require?

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

What is affected?

The Linux Kernel Organization · Linuxversion=501ef3066c89d7f9045315e1be58749cf9e6814d <0ce6052802be2cb61a57b753e41301339c88c839; version=501ef3066c89d7f9045315e1be58749cf9e6814d <333980481b99edb24ebd5d1a53af70a15d9146de; version=501ef3066c89d7f9045315e1be58749cf9e6814d <9d1ba11fabdd8f25abb24272ef1621417981320b; version=501ef3066c89d7f9045315e1be58749cf9e6814d <b5bba6ede42693f50ce1c9944315cefed7491061; version=5.10
The Linux Kernel Organization · Linux Kernelversion=501ef3066c89 <0ce6052802be; version=501ef3066c89 <333980481b99; version=501ef3066c89 <9d1ba11fabdd; version=501ef3066c89 <b5bba6ede426; version=5.10

Published CVSS scores

8.2UbuntuCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/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.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

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

No sourced classifications are available.

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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