CVE-2021-46947

Kernel crash via uninitialized sfc queue entries

Published Feb 27, 2024 · Updated May 11, 2026

NULL pointer dereference in Linux sfc driver 5.12 through 5.12.2 allows local users to crash the kernel via ethtool statistics. During probing, the driver leaves some efx->xdp_tx_queues entries null but retains a CPU-based count, so efx_ethtool_get_stats traverses beyond initialized queues. Exploitation requires local low-privilege access and an affected sfc interface; the demonstrated consequence is a kernel oops and service interruption.

CVSS severity5.5
Medium
EPSS probability0.19%
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 sfc driver 5.12 through 5.12.2 allows local users to crash the kernel via ethtool statistics. During probing, the driver leaves some efx->xdp_tx_queues entries null but retains a CPU-based count, so efx_ethtool_get_stats traverses beyond initialized queues. Exploitation requires local low-privilege access and an affected sfc interface; the demonstrated consequence is a kernel oops and service interruption.

The record

CVE
CVE-2021-46947
Published
Feb 27, 2024
Updated
May 11, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
CWE-476, T1499.004
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Feb 27, 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=e26ca4b535820b1445dcef3c0f82b3fb5b45108b <99ba0ea616aabdc8e26259fd722503e012199a76
  3. Affected versionversion=e26ca4b535820b1445dcef3c0f82b3fb5b45108b <ebeac958b690123a0b40aa61f688f2f170035fad

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=5.12; version=e26ca4b535820b1445dcef3c0f82b3fb5b45108b <99ba0ea616aabdc8e26259fd722503e012199a76; version=e26ca4b535820b1445dcef3c0f82b3fb5b45108b <ebeac958b690123a0b40aa61f688f2f170035fad

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.

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)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-476NULL Pointer Dereference
T1499.004Application or System Exploitation

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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