CVE-2021-40327

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.

Published: 2022-01-13 Last update: 2026-06-05 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2021-40327 is rated Moderate Risk (41.8/100): CVSS Medium severity, with medium exploitation likelihood (EPSS 0.33%). Review affected assets and schedule remediation.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2021-40327

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2025-03-30 0.64% 0.33% -0.31%
2 2025-03-29 0.33% 0.64% +0.31%
3 2025-03-17 — 0.33% —

Full EPSS history (7 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2021-40327

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
5.9 3.1 MEDIUM
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:H)
Even with access, the exploit needs extra luck, timing, or a fussy environment to actually work.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:N)
Service keeps running; no real outage angle.
 2.2 3.6 [email protected]
2.6 2.0 LOW
AV:N/AC:H/Au:N/C:P/I:N/A:N Click to expand
Access vector (AV:N)
Can be exploited remotely over network reachability.
Access complexity (AC:H)
Exploitation requires uncommon or highly specific conditions.
Authentication (AU:N)
No authentication is required.
Confidentiality impact (C:P)
Partial confidentiality impact.
Integrity impact (I:N)
No integrity impact.
Availability impact (A:N)
No availability impact.
 4.9 2.9 [email protected]

Weakness enumeration for CVE-2021-40327

GitHub Security Advisory for CVE-2021-40327

GHSA-p88f-g9m7-hv9c · Severity: medium — Trusted Firmware-M (TF-M) 1.4.0, when Profile Small is used, has incorrect access control. NSPE...

OS Trackers for CVE-2021-40327

vendor priority summary link
ubuntu high CVE-2021-40327 high priority: Ubuntu including 1 source packages (arm-trusted-firmware), 14 status rows across 14 suites (focal, hirsute, impish, jammy, kinetic, lunar, mantic, noble, oracular, plucky, questing, trusty, upstream, xenial): ignored 9, not-affected 4, needs-triage 1. https://ubuntu.com/security/CVE-2021-40327

Affected software / configurations for CVE-2021-40327

Vendor Product Version Raw CPE
trustedfirmware trusted_firmware-m 1.4.0 cpe:2.3:o:trustedfirmware:trusted_firmware-m:1.4.0:*:*:*:*:*:*:*

References for CVE-2021-40327

cvelogic Threat Intelligence