CVE-2021-47424

Local kernel crash via premature IRQ free

Published May 21, 2024 · Updated May 11, 2026

A resource-management flaw in the Linux i40e driver allows local users to crash the kernel when PF switch setup fails during probing. On that error path, i40e_clear_interrupt_scheme calls i40e_free_misc_vector before __I40E_MISC_IRQ_REQUESTED is set, freeing an IRQ that was never allocated. Reachability requires local access, an i40e-managed Intel NIC, and a PF/VSI initialization failure; the documented result is a kernel Oops and service interruption.

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

A resource-management flaw in the Linux i40e driver allows local users to crash the kernel when PF switch setup fails during probing. On that error path, i40e_clear_interrupt_scheme calls i40e_free_misc_vector before __I40E_MISC_IRQ_REQUESTED is set, freeing an IRQ that was never allocated. Reachability requires local access, an i40e-managed Intel NIC, and a PF/VSI initialization failure; the documented result is a kernel Oops and service interruption.

The record

CVE
CVE-2021-47424
Published
May 21, 2024
Updated
May 11, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
CWE-908, 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=4.15
  2. Affected versionversion=c17401a1dd210a5f22ab1ec7c7366037c158a14c <17063cac4088b8e2fc0f633abddca5426ed58312
  3. Affected versionversion=c17401a1dd210a5f22ab1ec7c7366037c158a14c <2e5a20573a926302b233b0c2e1077f5debc7ab2e
  4. Affected versionversion=c17401a1dd210a5f22ab1ec7c7366037c158a14c <60ad4cde0ad28921f9ea25b0201c774b95ffa4b4
  5. Affected versionversion=c17401a1dd210a5f22ab1ec7c7366037c158a14c <75099439209d3cda439a1d9b00d19a50f0066fef
  6. Affected versionversion=c17401a1dd210a5f22ab1ec7c7366037c158a14c <97aeed72af4f83ae51534f0a2473ff52f8d66236

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=4.15; version=c17401a1dd210a5f22ab1ec7c7366037c158a14c <17063cac4088b8e2fc0f633abddca5426ed58312; version=c17401a1dd210a5f22ab1ec7c7366037c158a14c <2e5a20573a926302b233b0c2e1077f5debc7ab2e; version=c17401a1dd210a5f22ab1ec7c7366037c158a14c <60ad4cde0ad28921f9ea25b0201c774b95ffa4b4; version=c17401a1dd210a5f22ab1ec7c7366037c158a14c <75099439209d3cda439a1d9b00d19a50f0066fef; version=c17401a1dd210a5f22ab1ec7c7366037c158a14c <97aeed72af4f83ae51534f0a2473ff52f8d66236

Published CVSS scores

5.5NIST NVDCVSS: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 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-908Use of Uninitialized Resource
T1499Endpoint Denial of Service

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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