CVE-2021-46916

Local system crash via missing q_vector check

Published Feb 27, 2024 · Updated May 11, 2026

NULL pointer dereference in the Linux kernel ixgbe driver 5.11 through 5.11.15 allows local users to crash the system during a loopback test. In ixgbe_setup_rx_resources, the driver reads rx_ring->q_vector->napi.napi_id even though interrupt-free test rings have no q_vector. Triggering the path requires administrative network capability, an ixgbe-backed interface, and an ethtool loopback test; the reported consequence is a kernel crash.

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 the Linux kernel ixgbe driver 5.11 through 5.11.15 allows local users to crash the system during a loopback test. In ixgbe_setup_rx_resources, the driver reads rx_ring->q_vector->napi.napi_id even though interrupt-free test rings have no q_vector. Triggering the path requires administrative network capability, an ixgbe-backed interface, and an ethtool loopback test; the reported consequence is a kernel crash.

The record

CVE
CVE-2021-46916
Published
Feb 27, 2024
Updated
May 11, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
CWE-476, T1499
Attack vector
local
Privileges
admin

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=5.11
  2. Affected versionversion=b02e5a0ebb172c8276cea3151942aac681f7a4a6 <31166efb1cee348eb6314e9c0095d84cbeb66b9d
  3. Affected versionversion=b02e5a0ebb172c8276cea3151942aac681f7a4a6 <758d19098df4b0bbca9f40d6ae6c82c9c18b9bba

What conditions does exploitation require?

Attack vectorlocal
Required privilegesadmin

What is affected?

The Linux Kernel Organization · Linuxversion=5.11; version=b02e5a0ebb172c8276cea3151942aac681f7a4a6 <31166efb1cee348eb6314e9c0095d84cbeb66b9d; version=b02e5a0ebb172c8276cea3151942aac681f7a4a6 <758d19098df4b0bbca9f40d6ae6c82c9c18b9bba

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
Privilegesadmin
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-476NULL Pointer Dereference
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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