Cyber Resilience

CVE-2025-21361

HighUpdated

Published: 14 January 2025

Published
14 January 2025
Modified
19 May 2026
KEV Added
Patch
CVSS Score v3.1 7.8 CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
EPSS Score 0.0070 72.5th percentile
Risk Priority 16 60% EPSS · 20% KEV · 20% CVSS

Summary

CVE-2025-21361 is a high-severity Improper Restriction of Names for Files and Other Resources (CWE-641) vulnerability in Microsoft Office. Its CVSS base score is 7.8 (High).

Operationally, exploitation aligns with the MITRE ATT&CK technique Exploitation for Client Execution (T1203); ranked in the top 27.5% of CVEs by exploit likelihood; it is not currently listed in the CISA KEV catalog.

The strongest mitigations our analysis identified are NIST 800-53 SI-2 (Flaw Remediation) and SI-3 (Malicious Code Protection).

Deeper analysis

CVE-2025-21361 is a Remote Code Execution vulnerability affecting Microsoft Outlook. Published on 2025-01-14, it carries a CVSS v3.1 base score of 7.8 (AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H) and is associated with CWE-641 and NVD-CWE-noinfo.

Exploitation requires local access to the target system, low attack complexity, no special privileges, and user interaction. A local attacker could leverage this to execute arbitrary code, resulting in high impacts to confidentiality, integrity, and availability on the affected system.

The Microsoft Security Response Center provides details on mitigation and patches in its update guide at https://msrc.microsoft.com/update-guide/vulnerability/CVE-2025-21361.

EU & UK References

Vulnerability details

Microsoft Outlook Remote Code Execution Vulnerability

CWE(s)

Related Threats

MITRE ATT&CK Enterprise TechniquesAI

T1203 Exploitation for Client Execution Execution
Adversaries may exploit software vulnerabilities in client applications to execute code.
Why these techniques?

The CVE describes a client-side RCE vulnerability in Microsoft Outlook requiring local access and user interaction to execute arbitrary code, directly mapping to exploitation of client applications for code execution.

Confidence: HIGH · MITRE ATT&CK Enterprise v18.1

CVEs Like This One

CVE-2025-21402Same product: Microsoft Office
CVE-2025-24080Same product: Microsoft Office
CVE-2025-53740Same product: Microsoft Office
CVE-2026-20952Same product: Microsoft Office
CVE-2025-53731Same product: Microsoft Office
CVE-2026-42831Same product: Microsoft Office
CVE-2026-40358Same product: Microsoft Office
CVE-2026-40363Same product: Microsoft Office
CVE-2026-26110Same product: Microsoft Office
CVE-2025-21354Same product: Microsoft Office

Affected Assets

microsoft
office
2024
microsoft
office long term servicing channel
2021
microsoft
outlook
≤ 16.93

Mitigating Controls

Mitigating Controls (NIST 800-53 r5) AI

prevent

Directly remediates the specific flaw in Microsoft Outlook by requiring timely patching as provided by Microsoft Security Response Center.

prevent

Deploys malicious code protection on user devices to scan and block potentially exploitable content in Outlook such as malicious attachments requiring user interaction.

prevent

Implements memory protections like DEP and ASLR to mitigate remote code execution exploits even if the Outlook vulnerability is triggered.

References