CVE-2021-47514

Local denial of service via netns reference leak

Published May 24, 2024 · Updated May 11, 2026

Reference-count leakage in Linux kernel devlink reload handling allows local users to exhaust kernel resources through failed reloads. In devlink_nl_cmd_reload(), error returns from devlink_reload() can bypass put_net(), retaining a network-namespace reference acquired by get_net(). The reload operation requires administrative permission; repeated failures consume references and can degrade system availability.

CVSS severity5.5
Medium
EPSS probability0.24%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Reference-count leakage in Linux kernel devlink reload handling allows local users to exhaust kernel resources through failed reloads. In devlink_nl_cmd_reload(), error returns from devlink_reload() can bypass put_net(), retaining a network-namespace reference acquired by get_net(). The reload operation requires administrative permission; repeated failures consume references and can degrade system availability.

The record

CVE
CVE-2021-47514
Published
May 24, 2024
Updated
May 11, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
CWE-911
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. May 24, 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

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=5.10
  2. Affected versionversion=ccdf07219da6bd1f43c6ddcde4c0e36993c7365a <4b7e90672af8e0c78205db006f1b0a20ebd07f5f
  3. Affected versionversion=ccdf07219da6bd1f43c6ddcde4c0e36993c7365a <4dbb0dad8e63fcd0b5a117c2861d2abe7ff5f186
  4. Affected versionversion=ccdf07219da6bd1f43c6ddcde4c0e36993c7365a <fe30b70ca84da9c4aca85c03ad86e7a9b89c5ded

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=5.10; version=ccdf07219da6bd1f43c6ddcde4c0e36993c7365a <4b7e90672af8e0c78205db006f1b0a20ebd07f5f; version=ccdf07219da6bd1f43c6ddcde4c0e36993c7365a <4dbb0dad8e63fcd0b5a117c2861d2abe7ff5f186; version=ccdf07219da6bd1f43c6ddcde4c0e36993c7365a <fe30b70ca84da9c4aca85c03ad86e7a9b89c5ded

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.

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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-911Improper Update of Reference Count

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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