CVE-2021-47225

System hang via recursive wiphy mutex acquisition

Published May 21, 2024 · Updated May 11, 2026

Deadlock in Linux kernel 5.12 allows local users to hang affected systems by closing an AP interface with active AP_VLAN interfaces. The mac80211 stop path calls dev_close() on VLAN interfaces while holding the wiphy mutex, and the cfg80211 netdev notifier recursively acquires that mutex. Reachability requires active AP_VLAN interfaces and permission to close their parent AP interface; the resulting lock inversion stalls kernel networking operations.

CVSS severity5.5
Medium
EPSS probability0.15%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Deadlock in Linux kernel 5.12 allows local users to hang affected systems by closing an AP interface with active AP_VLAN interfaces. The mac80211 stop path calls dev_close() on VLAN interfaces while holding the wiphy mutex, and the cfg80211 netdev notifier recursively acquires that mutex. Reachability requires active AP_VLAN interfaces and permission to close their parent AP interface; the resulting lock inversion stalls kernel networking operations.

The record

CVE
CVE-2021-47225
Published
May 21, 2024
Updated
May 11, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
T1499
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=5.12
  2. Affected versionversion=a05829a7222e9d10c416dd2dbbf3929fe6646b89 <8043903fcb72f545c52e3ec74d6fd82ef79ce7c5
  3. Affected versionversion=a05829a7222e9d10c416dd2dbbf3929fe6646b89 <d5befb224edbe53056c2c18999d630dafb4a08b9

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=5.12; version=a05829a7222e9d10c416dd2dbbf3929fe6646b89 <8043903fcb72f545c52e3ec74d6fd82ef79ce7c5; version=a05829a7222e9d10c416dd2dbbf3929fe6646b89 <d5befb224edbe53056c2c18999d630dafb4a08b9

Published CVSS scores

5.5CISA-ADPCVSS: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 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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