Cyber Posture

CVE-2025-21392

High

Published: 11 February 2025

Published
11 February 2025
Modified
01 July 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 0.0035 57.4th percentile
Risk Priority 16 60% EPSS · 20% KEV · 20% CVSS

Summary

CVE-2025-21392 is a high-severity Use After Free (CWE-416) vulnerability in Microsoft Office Long Term Servicing Channel. 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 42.6% 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-16 (Memory Protection) and SI-2 (Flaw Remediation).

Threat & Defense at a Glance

What attackers do: exploitation maps to Exploitation for Client Execution (T1203) and 1 other technique. What defenders deploy: see the NIST 800-53 controls recommended below.
Threat & Defense Details

Mitigating Controls (NIST 800-53 r5)AI

prevent

Requires timely installation of Microsoft patches to remediate the Use After Free vulnerability in Office, directly preventing exploitation.

prevent

Implements memory safeguards such as DEP and ASLR that protect against unauthorized code execution from Use After Free flaws.

detect

Enables vulnerability scanning to identify CVE-2025-21392 in Microsoft Office systems, supporting prioritization for patching.

MITRE ATT&CK Enterprise TechniquesAI

T1203 Exploitation for Client Execution Execution
Adversaries may exploit software vulnerabilities in client applications to execute code.
T1204.002 Malicious File Execution
An adversary may rely upon a user opening a malicious file in order to gain execution.
Why these techniques?

RCE vulnerability in Microsoft Office via use-after-free requires user interaction to open malicious file, directly enabling client-side exploitation and malicious file execution.

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

NVD Description

Microsoft Office Remote Code Execution Vulnerability

Deeper analysisAI

CVE-2025-21392 is a remote code execution vulnerability in Microsoft Office, published on 2025-02-11. It stems from CWE-416 (Use After Free) with additional NVD-CWE-noinfo classification and 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).

Exploitation requires local access vector with low attack complexity and no privileges, but user interaction is necessary. A threat actor can leverage this to execute arbitrary code on the target system, resulting in high impacts to confidentiality, integrity, and availability.

Microsoft provides mitigation details, including patches, in its Security Response Center update guide at https://msrc.microsoft.com/update-guide/vulnerability/CVE-2025-21392.

Details

CWE(s)

Affected Products

microsoft
365 apps
all versions
microsoft
office
2016, 2019
microsoft
office long term servicing channel
2021, 2024

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References