CVE-2021-29414Public exploit

Flash alteration via fault-suppressed mass erase

Published May 21, 2021 · Updated Aug 3, 2024

Physical access control failure in STMicroelectronics STM32L4 devices through 2021-03-29 allows physically proximate attackers to alter flash. During a read-out protection transition, electromagnetic fault injection suppresses the mandatory mass erase while debug access is re-enabled. Physical chip access and fault-injection equipment are required; exploitation permits protected firmware modification or device interruption.

CVSS severity6.1
Medium
EPSS probability0.33%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Physical access control failure in STMicroelectronics STM32L4 devices through 2021-03-29 allows physically proximate attackers to alter flash. During a read-out protection transition, electromagnetic fault injection suppresses the mandatory mass erase while debug access is re-enabled. Physical chip access and fault-injection equipment are required; exploitation permits protected firmware modification or device interruption.

The record

CVE
CVE-2021-29414
Published
May 21, 2021
Updated
Aug 3, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-74
Attack vector
physical
Privileges
unauthenticated

Timeline

How it unfolded

  1. May 21, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 3, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectorphysical
Required privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

3.6NIST NVDAV:L/AC:L/Au:N/C:N/I:P/A:P
6.1NIST NVDCVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:U/C:N/I:H/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)
Vectorphysical
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-74Improper Neutralization of Special Elements in Output Used by a Downstream Component ('Injection')

Public exploit references

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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