Cyber Resilience

CVE-2025-21363

Microsoft Office Long Term Servicing Channel 2021 … 2024

Published
14 January 2025
Modified
01 July 2025
Patch / advisory
View advisory
CVSS Score v3.1 7.8
Click a component to see what it means
Raw vectorCVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
EPSS Score 0.0076 52th percentile
Risk Priority 61 floored blend · peak EPSS

Summary

CVE-2025-21363 is a high-severity Untrusted Pointer Dereference (CWE-822) 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 Privilege Escalation (T1068); ranked in the top 48% of CVEs by exploit likelihood; it is not currently listed in the CISA KEV catalog.

The strongest mitigations our analysis identified map to SA-11 (Developer Testing and Evaluation) and SI-10 (Information Input Validation) — see the control section below for these in your framework.

Deeper analysis AI-assisted summary

Synthesised by an AI model from the NVD description and linked references — a reading aid, not an authoritative source.

Microsoft Word contains a remote code execution vulnerability tracked as CVE-2025-21363. The flaw affects the Microsoft Word application and carries a CVSS 3.1 base score of 7.8, reflecting local attack vector, low attack complexity, no privileges required, and required user interaction, with high impact on confidentiality, integrity, and availability. The issue is associated with CWE-822.

An attacker can exploit the vulnerability by supplying a specially crafted file that a user opens in Microsoft Word. Successful exploitation grants the attacker the ability to execute arbitrary code in the context of the current user, potentially leading to full control over affected documents and system resources.

Microsoft has published guidance for the vulnerability in its Security Response Center update guide. The EPSS score remains low, with a current value of 0.0154 and a recorded peak of 0.0195, indicating limited observed exploitation interest to date.

EU & UK References

Vulnerability Data

Microsoft Word Remote Code Execution Vulnerability

CWE(s)
CWE-822NVD-CWE-noinfo

Related Threats

MITRE ATT&CK Enterprise Techniques

T1068 Exploitation for Privilege Escalation Privilege Escalation
Adversaries may exploit software vulnerabilities in an attempt to elevate privileges.
attack.mitre.org →
T1190 Exploit Public-Facing Application Initial Access
Adversaries may attempt to exploit a weakness in an Internet-facing host or system to initially access a network.
attack.mitre.org →
T1203 Exploitation for Client Execution Execution
Adversaries may exploit software vulnerabilities in client applications to execute code.
attack.mitre.org →
T1210 Exploitation of Remote Services Lateral Movement
Adversaries may exploit remote services to gain unauthorized access to internal systems once inside of a network.
attack.mitre.org →
T1212 Exploitation for Credential Access Credential Access
Adversaries may exploit software vulnerabilities in an attempt to collect credentials.
attack.mitre.org →
Derived from this CVE’s CWE(s) via the direct CWE→ATT&CK cross-walk.

CVEs Like This One

CVE-2026-33114Same product: Microsoft 365 Apps
CVE-2026-20956Same product: Microsoft 365 Apps
CVE-2025-24083Same product: Microsoft 365 Apps
CVE-2023-36045Same product: Microsoft 365 Apps
CVE-2025-60728Same product: Microsoft 365 Apps
CVE-2024-21384Same product: Microsoft 365 Apps
CVE-2026-20955Same product: Microsoft 365 Apps
CVE-2024-38172Same product: Microsoft 365 Apps
CVE-2025-21354Same product: Microsoft 365 Apps
CVE-2026-26113Same product: Microsoft 365 Apps

Affected Assets

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

Mitigating Controls

Mitigating Controls (NIST 800-53 r5) AI

SA-11 Developer Testing and Evaluation good match

Developer testing and evaluation can discover instances where untrusted data is turned into a pointer and dereferenced.

SI-10 Information Input Validation good match

Validating all information inputs stops untrusted values from being accepted and converted into dereferenceable pointers.

SI-16 Memory Protection partial match

Memory-protection mechanisms limit the damage from an invalid pointer dereference without stopping the root coding flaw.

Mitigating Controls (NIST CSF 2.0) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.

PR.PS-06 mostly match
prevents

Secure SDLC practices directly prevent introduction of untrusted pointer handling during development.

DE.CM-09 partial match
prevents

Runtime monitoring of software and data can detect adverse events resulting from exploitation of the weakness.

ID.RA-01 partial match
prevents

Vulnerability identification processes can discover instances of this weakness via code review or scanning.

Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.

A.8.29 Security testing in development and acceptance mostly match
finds

Security testing can detect pointer-dereference flaws before release.

A.8.25 Secure development life cycle partial match
prevents

Secure development lifecycle includes pointer-safety practices that reduce untrusted pointer dereference risk.

A.8.26 Application security requirements partial match
prevents

Application security requirements can mandate validation of pointers obtained from untrusted sources.

A.8.27 Secure system architecture and engineering principles partial match
prevents

Secure architecture principles discourage direct use of untrusted values as pointers.

A.8.28 Secure coding partial match
prevents

Secure coding standards explicitly forbid dereferencing pointers derived from untrusted input.

References