CVE-2021-38576Network attack vector

TPM bricking via empty Platform authorization

Published Jan 3, 2022 · Updated Nov 3, 2025

Security feature bypass in TianoCore EDK II firmware through stable 202105 allows attackers to cause TPM bricking or system service interruption via BIOS operations. The firmware leaves the TPM Platform authorization value empty, so platform-hierarchy commands can permanently brick the TPM or trigger a non-permanent denial of service. Exploitation requires a vulnerable firmware build on the affected PC model; the record does not establish a safe remote interface or a non-destructive way to reproduce the failure.

CVSS severity7.5
High
EPSS probability1.17%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Security feature bypass in TianoCore EDK II firmware through stable 202105 allows attackers to cause TPM bricking or system service interruption via BIOS operations. The firmware leaves the TPM Platform authorization value empty, so platform-hierarchy commands can permanently brick the TPM or trigger a non-permanent denial of service. Exploitation requires a vulnerable firmware build on the affected PC model; the record does not establish a safe remote interface or a non-destructive way to reproduce the failure.

The record

CVE
CVE-2021-38576
Published
Jan 3, 2022
Updated
Nov 3, 2025
Vendor
TianoCore
Product
EDK II
Classifications
T1490
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jan 3, 2022CVE publishedPublication date reported by the CVE source.
  2. Nov 3, 2025Record 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=edk2-stable202105, edk2-stable202102, edk2-stable202011, edk2-stable202008, edk2-stable202005, edk2-stable202002, edk2-stable201911, edk2-stable201908, edk2-stable201905, edk2-stable201903, edk2-stable201811, edk2-stable201808

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

TianoCore · EDK IIversion=edk2-stable202105, edk2-stable202102, edk2-stable202011, edk2-stable202008, edk2-stable202005, edk2-stable202002, edk2-stable201911, edk2-stable201908, edk2-stable201905, edk2-stable201903, edk2-stable201811, edk2-stable201808

Published CVSS scores

7.8NVDAV:N/AC:L/Au:N/C:N/I:N/A:C
7.5NVDCVSS:3.1/AV:N/AC:L/PR:N/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.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

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

T1490Inhibit System Recovery

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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