CVE-2021-47235

Kernel compromise via premature network-device private-data release

Published May 21, 2024 · Updated May 11, 2026

Use-after-free in the ec_bhf Ethernet driver in Linux allows local users to compromise the kernel through PCI device removal. ec_bhf_remove calls free_netdev before reading priv->dma_io and priv->io for pci_iounmap, dereferencing private data owned by the freed net_device. The affected path requires the ec_bhf driver and PCI-device teardown; a successful trigger can crash or compromise the kernel.

CVSS severity7.8
High
EPSS probability0.23%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Use-after-free in the ec_bhf Ethernet driver in Linux allows local users to compromise the kernel through PCI device removal. ec_bhf_remove calls free_netdev before reading priv->dma_io and priv->io for pci_iounmap, dereferencing private data owned by the freed net_device. The affected path requires the ec_bhf driver and PCI-device teardown; a successful trigger can crash or compromise the kernel.

The record

CVE
CVE-2021-47235
Published
May 21, 2024
Updated
May 11, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
CWE-416, T1068
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=3.15
  2. Affected versionversion=6af55ff52b02d492d45db88df3e461fa51a6f753 <0260916843cc74f3906acf8b6f256693e01530a2
  3. Affected versionversion=6af55ff52b02d492d45db88df3e461fa51a6f753 <19f88ca68ccf8771276a606765239b167654f84a
  4. Affected versionversion=6af55ff52b02d492d45db88df3e461fa51a6f753 <1cafc540b7bf1b6a5a77dc000205fe337ef6eba6
  5. Affected versionversion=6af55ff52b02d492d45db88df3e461fa51a6f753 <95deeb29d831e2fae608439e243e7a520611e7ea
  6. Affected versionversion=6af55ff52b02d492d45db88df3e461fa51a6f753 <9cca0c2d70149160407bda9a9446ce0c29b6e6c6
  7. Affected versionversion=6af55ff52b02d492d45db88df3e461fa51a6f753 <b1ad283755095a4b9d1431aeb357d7df1a33d3bb
  8. Affected versionversion=6af55ff52b02d492d45db88df3e461fa51a6f753 <d11d79e52ba080ee567cb7d7eb42a5ade60a8130
  9. Affected versionversion=6af55ff52b02d492d45db88df3e461fa51a6f753 <db2bc3cfd2bc01621014d4f17cdfc74611f339c8

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=3.15; version=6af55ff52b02d492d45db88df3e461fa51a6f753 <0260916843cc74f3906acf8b6f256693e01530a2; version=6af55ff52b02d492d45db88df3e461fa51a6f753 <19f88ca68ccf8771276a606765239b167654f84a; version=6af55ff52b02d492d45db88df3e461fa51a6f753 <1cafc540b7bf1b6a5a77dc000205fe337ef6eba6; version=6af55ff52b02d492d45db88df3e461fa51a6f753 <95deeb29d831e2fae608439e243e7a520611e7ea; version=6af55ff52b02d492d45db88df3e461fa51a6f753 <9cca0c2d70149160407bda9a9446ce0c29b6e6c6; version=6af55ff52b02d492d45db88df3e461fa51a6f753 <b1ad283755095a4b9d1431aeb357d7df1a33d3bb; version=6af55ff52b02d492d45db88df3e461fa51a6f753 <d11d79e52ba080ee567cb7d7eb42a5ade60a8130; version=6af55ff52b02d492d45db88df3e461fa51a6f753 <db2bc3cfd2bc01621014d4f17cdfc74611f339c8

Published CVSS scores

7.8NIST NVDCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
5.5SUSECVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
7.8Canonical UbuntuCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/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 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-416Use After Free
T1068Exploitation for Privilege Escalation

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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