CVE-2021-47622

Local storage hang via UFS request deadlock

Published Jul 16, 2024 · Updated May 23, 2026

Improper locking in the Linux kernel UFS driver allows local users to hang storage error recovery when all request tags are allocated. The SCSI error path queues ufshcd_err_handler(), whose reset flow calls ufshcd_exec_dev_cmd() and waits for an ordinary request tag even though none is free. A host must use the UFS driver, exhaust every normal tag, and enter SCSI host-reset recovery; the resulting deadlock stalls UFS recovery and storage service.

CVSS severity5.5
Medium
EPSS probability0.17%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper locking in the Linux kernel UFS driver allows local users to hang storage error recovery when all request tags are allocated. The SCSI error path queues ufshcd_err_handler(), whose reset flow calls ufshcd_exec_dev_cmd() and waits for an ordinary request tag even though none is free. A host must use the UFS driver, exhaust every normal tag, and enter SCSI host-reset recovery; the resulting deadlock stalls UFS recovery and storage service.

The record

CVE
CVE-2021-47622
Published
Jul 16, 2024
Updated
May 23, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
CWE-667, T1499.004
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Jul 16, 2024CVE publishedPublication date reported by the CVE source.
  2. May 23, 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=5.4.112 <5.5
  2. Affected versionversion=5.6
  3. Affected versionversion=7252a3603015f1fd04363956f4b72a537c9f9c42 <493c9e850677df8b4eda150c2364b1c1a72ed724
  4. Affected versionversion=7252a3603015f1fd04363956f4b72a537c9f9c42 <945c3cca05d78351bba29fa65d93834cb7934c7b
  5. Affected versionversion=7252a3603015f1fd04363956f4b72a537c9f9c42 <d69d98d8edf90e25e4e09930dd36dd6d09dd6768
  6. Affected versionversion=a8d2d45c70c7391386baf7863674f156da56a3d5

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=5.4.112 <5.5; version=5.6; version=7252a3603015f1fd04363956f4b72a537c9f9c42 <493c9e850677df8b4eda150c2364b1c1a72ed724; version=7252a3603015f1fd04363956f4b72a537c9f9c42 <945c3cca05d78351bba29fa65d93834cb7934c7b; version=7252a3603015f1fd04363956f4b72a537c9f9c42 <d69d98d8edf90e25e4e09930dd36dd6d09dd6768; version=a8d2d45c70c7391386baf7863674f156da56a3d5

Published CVSS scores

5.5NVDCVSS: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-667Improper Locking
T1499.004Application or System Exploitation

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

See the directory against your own environment.

Your stack

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