Cyber Posture

CVE-2025-21345

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 0.0092 76.1th percentile
Risk Priority 16 60% EPSS · 20% KEV · 20% CVSS

Summary

CVE-2025-21345 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 23.9% 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-16 (Memory Protection).

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 Use After Free vulnerability by requiring timely installation of Microsoft patches for affected Visio versions.

prevent

Implements memory safeguards such as DEP and ASLR to protect against code execution exploits stemming from the Visio Use After Free flaw.

preventdetect

Deploys malicious code protection to scan and block malicious Visio files that could trigger the remote code execution 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?

This client-side RCE vulnerability in Microsoft Visio requires user interaction to open a malicious file (UI:R, AV:L) and directly enables arbitrary code execution, mapping to Exploitation for Client Execution (T1203) and User Execution via Malicious File (T1204.002).

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

NVD Description

Microsoft Office Visio Remote Code Execution Vulnerability

Deeper analysisAI

CVE-2025-21345 is a Remote Code Execution vulnerability affecting Microsoft Office Visio. Published on 2025-01-14, it has 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-416 (Use After Free), though additional CWE details are unavailable from NVD.

The vulnerability can be exploited by an attacker with local access to the target system, requiring low attack complexity, no privileges, and user interaction. A successful exploit allows the attacker to achieve high-impact remote code execution, compromising confidentiality, integrity, and availability on the affected system.

The Microsoft Security Response Center advisory at https://msrc.microsoft.com/update-guide/vulnerability/CVE-2025-21345 provides details on mitigation, including available patches.

Details

CWE(s)

Affected Products

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

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References