CVE-2021-47283

Service interruption via unreleased legacy IRQ

Published May 21, 2024 · Updated May 11, 2026

Resource-release failure in Linux 5.9 through 5.10.43, 5.11 through 5.12.10, and 5.13 release candidates allows local users to interrupt service. The SFC legacy-interrupt initialization path leaves irqs_hooked unset after requesting the IRQ, so module teardown skips its release. Reachability requires an SFC adapter configured for legacy IRQ mode and permission to remove its kernel module; the stale IRQ produces kernel warnings and availability loss.

CVSS severity5.5
Medium
EPSS probability0.22%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Resource-release failure in Linux 5.9 through 5.10.43, 5.11 through 5.12.10, and 5.13 release candidates allows local users to interrupt service. The SFC legacy-interrupt initialization path leaves irqs_hooked unset after requesting the IRQ, so module teardown skips its release. Reachability requires an SFC adapter configured for legacy IRQ mode and permission to remove its kernel module; the stale IRQ produces kernel warnings and availability loss.

The record

CVE
CVE-2021-47283
Published
May 21, 2024
Updated
May 11, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
CWE-772, T1499
Attack vector
local
Privileges
authenticated

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=5.9
  2. Affected versionversion=e6a43910d55d09dae65772ad571d4c61e459b17a <81c4d1d83f88e15b26f4522a35cba6ffd8c5dfdd
  3. Affected versionversion=e6a43910d55d09dae65772ad571d4c61e459b17a <8d717c9135a3340ae62d1699484850bfb4112b0c
  4. Affected versionversion=e6a43910d55d09dae65772ad571d4c61e459b17a <8f03eeb6e0a0a0b8d617ee0a4bce729e47130036

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=5.9; version=e6a43910d55d09dae65772ad571d4c61e459b17a <81c4d1d83f88e15b26f4522a35cba6ffd8c5dfdd; version=e6a43910d55d09dae65772ad571d4c61e459b17a <8d717c9135a3340ae62d1699484850bfb4112b0c; version=e6a43910d55d09dae65772ad571d4c61e459b17a <8f03eeb6e0a0a0b8d617ee0a4bce729e47130036

Published CVSS scores

5.5NIST NVDCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
5.5SUSECVSS: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 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-772Missing Release of Resource after Effective Lifetime
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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