CVE-2021-47127

Kernel crash via misrouted AF_XDP copy-mode queues

Published Mar 15, 2024 · Updated May 11, 2026

NULL pointer dereference in Linux 5.12 through 5.12.9 allows local users to crash the kernel through AF_XDP copy-mode transmit traffic. The ice driver sets xsk_pool based only on an XDP program's presence, dispatching copy-mode queues to ice_clean_tx_irq_zc instead of ice_clean_tx_irq. Reaching the fault requires an Intel ice interface, an attached XDP program, and xdpsock-style txonly or l2fwd traffic in copy mode.

CVSS severity5.5
Medium
EPSS probability0.20%
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 Linux 5.12 through 5.12.9 allows local users to crash the kernel through AF_XDP copy-mode transmit traffic. The ice driver sets xsk_pool based only on an XDP program's presence, dispatching copy-mode queues to ice_clean_tx_irq_zc instead of ice_clean_tx_irq. Reaching the fault requires an Intel ice interface, an attached XDP program, and xdpsock-style txonly or l2fwd traffic in copy mode.

The record

CVE
CVE-2021-47127
Published
Mar 15, 2024
Updated
May 11, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
T1499
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Mar 15, 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=5.12
  2. Affected versionversion=c7a219048e459cf99c6fec0f7c1e42414e9e6202 <1d34fa4fcf06649036ba0c97854fcf7a741ee18c
  3. Affected versionversion=c7a219048e459cf99c6fec0f7c1e42414e9e6202 <e102db780e1c14f10c70dafa7684af22a745b51d

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=5.12; version=c7a219048e459cf99c6fec0f7c1e42414e9e6202 <1d34fa4fcf06649036ba0c97854fcf7a741ee18c; version=c7a219048e459cf99c6fec0f7c1e42414e9e6202 <e102db780e1c14f10c70dafa7684af22a745b51d

Published CVSS scores

5.5UbuntuCVSS: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

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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