CVE-2019-20811

Local network-device hang via negative reference count

Published Jun 3, 2020 · Updated Aug 5, 2024

Reference-counting error in the Linux kernel before 5.0.6 allows local users to hang network-device unregistration after sysfs setup fails. When sysfs_create_group fails in rx_queue_add_kobject or netdev_queue_add_kobject, kobject_put invokes netdev_queue_release before dev_hold acquires a device reference, driving the usage count below zero. Local low-privileged access is required, and unregister_netdevice then waits indefinitely for the device to become free.

CVSS severity5.5
Medium
EPSS probability0.44%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Reference-counting error in the Linux kernel before 5.0.6 allows local users to hang network-device unregistration after sysfs setup fails. When sysfs_create_group fails in rx_queue_add_kobject or netdev_queue_add_kobject, kobject_put invokes netdev_queue_release before dev_hold acquires a device reference, driving the usage count below zero. Local low-privileged access is required, and unregister_netdevice then waits indefinitely for the device to become free.

The record

CVE
CVE-2019-20811
Published
Jun 3, 2020
Updated
Aug 5, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
T1499
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Jun 3, 2020CVE publishedPublication date reported by the CVE source.
  2. Aug 5, 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 vectorlocal
Required privilegesauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

2.1NIST NVDAV:L/AC:L/Au:N/C:N/I:P/A:N
5.5NIST NVDCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N
5.5CanonicalCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N

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

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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