CVE-2021-37159

System crash via unregistered network device double-free

Published Jul 21, 2021 · Updated Aug 4, 2024

Double free in the Linux kernel through 5.13.4 allows physically proximate attackers to crash the system via a crafted USB device. The hso_free_net_device function calls unregister_netdev when the network device never reached NETREG_REGISTERED, releasing the same object twice. Reaching this path requires physical attachment of an Option USB High Speed Mobile device and a device-registration error; the bounded consequence is a kernel crash.

CVSS severity6.4
Medium
EPSS probability0.39%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Double free in the Linux kernel through 5.13.4 allows physically proximate attackers to crash the system via a crafted USB device. The hso_free_net_device function calls unregister_netdev when the network device never reached NETREG_REGISTERED, releasing the same object twice. Reaching this path requires physical attachment of an Option USB High Speed Mobile device and a device-registration error; the bounded consequence is a kernel crash.

The record

CVE
CVE-2021-37159
Published
Jul 21, 2021
Updated
Aug 4, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-415, CWE-416, T1499
Attack vector
physical
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jul 21, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 4, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectorphysical
Required privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

4.4NIST NVDAV:L/AC:M/Au:N/C:P/I:P/A:P
6.4NIST NVDCVSS:3.1/AV:P/AC:H/PR:N/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

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)
Vectorphysical
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-415Double Free
CWE-416Use After Free
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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