Cyber Posture

CVE-2025-21395

High

Published: 14 January 2025

Published
14 January 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 0.0206 84.0th percentile
Risk Priority 17 60% EPSS · 20% KEV · 20% CVSS

Summary

CVE-2025-21395 is a high-severity Heap-based Buffer Overflow (CWE-122) 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 16.0% 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

Directly remediates the Microsoft Access heap-based buffer overflow vulnerability by requiring timely identification, reporting, and patching of flaws like CVE-2025-21395.

prevent

Implements memory protections such as DEP, ASLR, and stack canaries that directly mitigate unauthorized code execution from heap buffer overflows (CWE-122) in Microsoft Access.

preventdetect

Deploys anti-malware tools to scan and block malicious Access files or detect code execution attempts exploiting the vulnerability.

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?

Client-side RCE in Microsoft Access via malicious file requiring user interaction directly enables T1203 (Exploitation for Client Execution) and T1204.002 (Malicious File).

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

NVD Description

Microsoft Access Remote Code Execution Vulnerability

Deeper analysisAI

CVE-2025-21395 is a Remote Code Execution vulnerability affecting Microsoft Access. 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-122 and NVD-CWE-noinfo.

Exploitation requires local access with low complexity and no privileges, but user interaction is necessary. 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 advisory at https://msrc.microsoft.com/update-guide/vulnerability/CVE-2025-21395 provides details on mitigation and patching guidance.

Details

CWE(s)

Affected Products

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

CVEs Like This One

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CVE-2025-49697Same product: Microsoft 365 Apps
CVE-2025-54910Same product: Microsoft 365 Apps
CVE-2025-21345Same product: Microsoft 365 Apps
CVE-2025-21392Same product: Microsoft 365 Apps

References