CVE-2021-47477Network attack vector

Kernel stack disclosure via fixed-length USB transfers

Published May 22, 2024 · Updated May 11, 2026

Information disclosure in the Linux kernel dt9812 driver allows attackers to receive 32 bytes of kernel stack data. The command helpers place USB transfer buffers on the kernel stack and always send 32 bytes, so short commands include unrelated stack contents. Exposure requires the dt9812 driver and a DT9812 USB device on a system where DMA mapping is not used; DMA-backed transfers instead fail.

CVSS severity5.3
Medium
EPSS probability0.72%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Information disclosure in the Linux kernel dt9812 driver allows attackers to receive 32 bytes of kernel stack data. The command helpers place USB transfer buffers on the kernel stack and always send 32 bytes, so short commands include unrelated stack contents. Exposure requires the dt9812 driver and a DT9812 USB device on a system where DMA mapping is not used; DMA-backed transfers instead fail.

The record

CVE
CVE-2021-47477
Published
May 22, 2024
Updated
May 11, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
Unavailable
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. May 22, 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=2.6.29
  2. Affected versionversion=63274cd7d38a3322d90b66a5bc976de1fb899051 <20cebb8b620dc987e55ddc46801de986e081757e
  3. Affected versionversion=63274cd7d38a3322d90b66a5bc976de1fb899051 <365a346cda82f51d835c49136a00a9df8a78c7f2
  4. Affected versionversion=63274cd7d38a3322d90b66a5bc976de1fb899051 <39ea61037ae78f14fa121228dd962ea3280eacf3
  5. Affected versionversion=63274cd7d38a3322d90b66a5bc976de1fb899051 <3ac273d154d634e2034508a14db82a95d7ad12ed
  6. Affected versionversion=63274cd7d38a3322d90b66a5bc976de1fb899051 <3efb7af8ac437085b6c776e5b54830b149d86efe
  7. Affected versionversion=63274cd7d38a3322d90b66a5bc976de1fb899051 <536de747bc48262225889a533db6650731ab25d3
  8. Affected versionversion=63274cd7d38a3322d90b66a5bc976de1fb899051 <786f5b03450454557ff858a8bead5d7c0cbf78d6
  9. Affected versionversion=63274cd7d38a3322d90b66a5bc976de1fb899051 <8a52bc480992c7c9da3ebfea456af731f50a4b97
  10. Affected versionversion=63274cd7d38a3322d90b66a5bc976de1fb899051 <a6af69768d5cb4b2528946d53be5fa19ade37723

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=2.6.29; version=63274cd7d38a3322d90b66a5bc976de1fb899051 <20cebb8b620dc987e55ddc46801de986e081757e; version=63274cd7d38a3322d90b66a5bc976de1fb899051 <365a346cda82f51d835c49136a00a9df8a78c7f2; version=63274cd7d38a3322d90b66a5bc976de1fb899051 <39ea61037ae78f14fa121228dd962ea3280eacf3; version=63274cd7d38a3322d90b66a5bc976de1fb899051 <3ac273d154d634e2034508a14db82a95d7ad12ed; version=63274cd7d38a3322d90b66a5bc976de1fb899051 <3efb7af8ac437085b6c776e5b54830b149d86efe; version=63274cd7d38a3322d90b66a5bc976de1fb899051 <536de747bc48262225889a533db6650731ab25d3; version=63274cd7d38a3322d90b66a5bc976de1fb899051 <786f5b03450454557ff858a8bead5d7c0cbf78d6; version=63274cd7d38a3322d90b66a5bc976de1fb899051 <8a52bc480992c7c9da3ebfea456af731f50a4b97; version=63274cd7d38a3322d90b66a5bc976de1fb899051 <a6af69768d5cb4b2528946d53be5fa19ade37723

Published CVSS scores

5.3CISA-ADPCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

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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)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

No sourced classifications are available.

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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