CVE-2021-40327Network attack vector

Secure-key disclosure via missing authorization

Published Jan 13, 2022 · Updated Aug 4, 2024

Missing authorization in Trusted Firmware-M 1.4.0 allows remote attackers to read secure keys via crafted key-ID requests. The Crypto service retrieves a key based only on the supplied identifier and does not verify the caller-to-key-owner relationship. Exploitation requires Profile Small with NSPE access to the Crypto service; the documented consequence is unauthorized confidentiality loss without integrity or availability impact.

CVSS severity5.9
Medium
EPSS probability1.19%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Missing authorization in Trusted Firmware-M 1.4.0 allows remote attackers to read secure keys via crafted key-ID requests. The Crypto service retrieves a key based only on the supplied identifier and does not verify the caller-to-key-owner relationship. Exploitation requires Profile Small with NSPE access to the Crypto service; the documented consequence is unauthorized confidentiality loss without integrity or availability impact.

The record

CVE
CVE-2021-40327
Published
Jan 13, 2022
Updated
Aug 4, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-862
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jan 13, 2022CVE publishedPublication date reported by the CVE source.
  2. Aug 4, 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 vectornetwork
Required privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

2.6NVDAV:N/AC:H/Au:N/C:P/I:N/A:N
5.9NVDCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N

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

CWE-862Missing Authorization

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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