Cyber Posture

CVE-2025-21361

High

Published: 14 January 2025

Published
14 January 2025
Modified
17 January 2025
KEV Added
Patch
CVSS Score 7.8 CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
EPSS Score 0.0052 66.9th 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 33.1% 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).

Threat & Defense at a Glance

What attackers do: exploitation maps to Exploitation for Client Execution (T1203). What defenders deploy: see the NIST 800-53 controls recommended below.
Threat & Defense Details

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.

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

NVD Description

Microsoft Outlook Remote Code Execution Vulnerability

Deeper analysisAI

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.

Details

CWE(s)

Affected Products

microsoft
office
2021, 2024
microsoft
outlook
≤ 16.93

CVEs Like This One

CVE-2025-21402Same product: Microsoft Office
CVE-2026-20952Same product: Microsoft Office
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CVE-2025-53731Same product: Microsoft Office
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CVE-2026-26110Same product: Microsoft Office
CVE-2025-62554Same product: Microsoft Office
CVE-2025-24080Same product: Microsoft Office
CVE-2025-49695Same product: Microsoft Office
CVE-2025-49697Same product: Microsoft Office

References