CVE-2021-47077

Local system crash via uninitialized shost_data dereference

Published Mar 1, 2024 · Updated May 11, 2026

NULL pointer dereference in the Linux kernel qedf driver allows local users to crash the system during a QED link-change event. The QED callback reaches qedf_update_link_speed before shost_data is initialized, then dereferences it while updating supported_speeds. Exposure requires the qedf FCoE driver and a supported QLogic adapter; the documented consequence is a kernel crash, not data disclosure or modification.

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

NULL pointer dereference in the Linux kernel qedf driver allows local users to crash the system during a QED link-change event. The QED callback reaches qedf_update_link_speed before shost_data is initialized, then dereferences it while updating supported_speeds. Exposure requires the qedf FCoE driver and a supported QLogic adapter; the documented consequence is a kernel crash, not data disclosure or modification.

The record

CVE
CVE-2021-47077
Published
Mar 1, 2024
Updated
May 11, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
CWE-476, T1499
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Mar 1, 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=4.11
  2. Affected versionversion=61d8658b4a435eac729966cc94cdda077a8df5cd <11014efcec378bb0050a6cf08eaf375e3693400a
  3. Affected versionversion=61d8658b4a435eac729966cc94cdda077a8df5cd <73578af92a0fae6609b955fcc9113e50e413c80f
  4. Affected versionversion=61d8658b4a435eac729966cc94cdda077a8df5cd <a6362a737572f66051deb7637f3f77ddf7a4402f

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=4.11; version=61d8658b4a435eac729966cc94cdda077a8df5cd <11014efcec378bb0050a6cf08eaf375e3693400a; version=61d8658b4a435eac729966cc94cdda077a8df5cd <73578af92a0fae6609b955fcc9113e50e413c80f; version=61d8658b4a435eac729966cc94cdda077a8df5cd <a6362a737572f66051deb7637f3f77ddf7a4402f

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

CWE-476NULL Pointer Dereference
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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