What is the CVSS score of CVE-2021-27562?

CVE-2021-27562 has a CVSS 3.1 base score of 5.5 (Medium). CVSS vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H. EPSS exploitation probability: 51.1%.

Is CVE-2021-27562 being actively exploited?

Yes, CVE-2021-27562 is listed in the CISA Known Exploited Vulnerabilities (KEV) catalog, confirming active in-the-wild exploitation. Immediate patching is required.

Trusted Firmware M CVE-2021-27562

MEDIUM

Out-of-bounds Write (CWE-787)

2021-05-25 cve@mitre.org

Memory Corruption Buffer Overflow Trusted Firmware M

5.5

CVSS 3.1 · NVD

Severity by source

NVD PRIMARY

5.5 MEDIUM

AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Primary rating from NVD · only source for this CVE.

CVSS VectorNVD

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Attack Vector

Local

Attack Complexity

Low

Privileges Required

Low

User Interaction

None

Scope

Unchanged

Confidentiality

None

Integrity

None

Availability

High

Lifecycle Timeline

Added to CISA KEV

Jun 05, 2026 - 20:31 CISA

CVE Published

May 25, 2021 - 19:15 cve.org

MEDIUM 5.5

DescriptionCVE.org

AnalysisAI

In Arm Trusted Firmware M through 1.2, the NS world may trigger a system halt, an overwrite of secure data, or the printing out of secure data when calling secure functions under the NSPE handler. Rated medium severity (CVSS 5.5), this vulnerability is low attack complexity. Actively exploited in the wild (cisa kev) and EPSS exploitation probability 51.1%.

Technical ContextAI

This vulnerability is classified as Out-of-bounds Write (CWE-787), which allows attackers to write data beyond allocated buffer boundaries leading to code execution or crashes. In Arm Trusted Firmware M through 1.2, the NS world may trigger a system halt, an overwrite of secure data, or the printing out of secure data when calling secure functions under the NSPE handler mode. Affected products include: Trustedfirmware Trusted Firmware-M. Version information: through 1.2.

RemediationAI

No vendor patch is available at time of analysis. Monitor vendor advisories for updates. Validate write boundaries, use memory-safe languages, enable compiler protections (ASLR, stack canaries).