CVE-2021-47416

Service interruption via leaked MDIO device memory

Published May 21, 2024 · Updated May 11, 2026

Memory leak in the MDIO bus interface in affected Linux kernel releases allows local users to interrupt service via registration failures. __mdiobus_register() leaves bus->state as MDIOBUS_ALLOCATED after device_register() runs, so mdiobus_free() calls kfree() instead of put_device() on failure. Exploitation requires local low-privileged access, and the published assessment limits the consequence to availability without data exposure or modification.

CVSS severity5.5
Medium
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

Memory leak in the MDIO bus interface in affected Linux kernel releases allows local users to interrupt service via registration failures. __mdiobus_register() leaves bus->state as MDIOBUS_ALLOCATED after device_register() runs, so mdiobus_free() calls kfree() instead of put_device() on failure. Exploitation requires local low-privileged access, and the published assessment limits the consequence to availability without data exposure or modification.

The record

CVE
CVE-2021-47416
Published
May 21, 2024
Updated
May 11, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
CWE-401, T1499.003
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=2.6.28
  2. Affected versionversion=46abc02175b3c246dd5141d878f565a8725060c9 <064c2616234a7394867c924b5c1303974f3a4f4d
  3. Affected versionversion=46abc02175b3c246dd5141d878f565a8725060c9 <0d2dd40a7be61b89a7c99dae8ee96389d27b413a
  4. Affected versionversion=46abc02175b3c246dd5141d878f565a8725060c9 <2250392d930bd0d989f24d355d6355b0150256e7
  5. Affected versionversion=46abc02175b3c246dd5141d878f565a8725060c9 <2397b9e118721292429fea8807a698e71b94795f
  6. Affected versionversion=46abc02175b3c246dd5141d878f565a8725060c9 <25e9f88c7e3cc35f5e3d3db199660d28a15df639
  7. Affected versionversion=46abc02175b3c246dd5141d878f565a8725060c9 <414bb4ead1362ef2c8592db723c017258f213988
  8. Affected versionversion=46abc02175b3c246dd5141d878f565a8725060c9 <ca6e11c337daf7925ff8a2aac8e84490a8691905
  9. Affected versionversion=46abc02175b3c246dd5141d878f565a8725060c9 <f4f502a04ee1e543825af78f47eb7785015cd9f6

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=2.6.28; version=46abc02175b3c246dd5141d878f565a8725060c9 <064c2616234a7394867c924b5c1303974f3a4f4d; version=46abc02175b3c246dd5141d878f565a8725060c9 <0d2dd40a7be61b89a7c99dae8ee96389d27b413a; version=46abc02175b3c246dd5141d878f565a8725060c9 <2250392d930bd0d989f24d355d6355b0150256e7; version=46abc02175b3c246dd5141d878f565a8725060c9 <2397b9e118721292429fea8807a698e71b94795f; version=46abc02175b3c246dd5141d878f565a8725060c9 <25e9f88c7e3cc35f5e3d3db199660d28a15df639; version=46abc02175b3c246dd5141d878f565a8725060c9 <414bb4ead1362ef2c8592db723c017258f213988; version=46abc02175b3c246dd5141d878f565a8725060c9 <ca6e11c337daf7925ff8a2aac8e84490a8691905; version=46abc02175b3c246dd5141d878f565a8725060c9 <f4f502a04ee1e543825af78f47eb7785015cd9f6

Published CVSS scores

5.5Amazon LinuxCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
5.5NVDCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
5.5UbuntuCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
3.3SUSECVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L

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-401Missing Release of Memory after Effective Lifetime
T1499.003Application Exhaustion Flood

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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