Security Resilience

CVE-2026-88150

Microsoft Office 2021

Published
13 October 2026
Modified
14 October 2026
Patch / advisory
View advisory
CVSS Score v3.1 8.8
Click a component to see what it means
Raw vectorCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
EPSS Score 0.0072 53th percentile
Risk Priority 65 floored blend · peak EPSS

CVSS and EPSS are reproduced from their sources (NVD, FIRST EPSS). Risk Priority is our own derived reading, not an NVD score.

Summary

CVE-2026-88150 is a high-severity Use of Uninitialized Resource (CWE-908) vulnerability in Microsoft Office 2021. Its CVSS base score is 8.8 (High).

Operationally, exploitation aligns with the MITRE ATT&CK technique OS Credential Dumping (T1003); ranked in the top 47% 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 SA-15 (Development Process, Standards, and Tools) — see the control section below for these in your framework.

EU & UK References

Vulnerability Data

Use of uninitialized resource in Microsoft Office Word allows an unauthorized attacker to execute code over a network.

CWE(s)
CWE-908

Related Threats

MITRE ATT&CK Enterprise Techniques

T1003 OS Credential Dumping Credential Access
Adversaries may attempt to dump credentials to obtain account login and credential material, normally in the form of a hash or a clear text password.
attack.mitre.org →
T1003.001 LSASS Memory Credential Access
Adversaries may attempt to access credential material stored in the process memory of the Local Security Authority Subsystem Service (LSASS).
attack.mitre.org →
T1003.002 Security Account Manager Credential Access
Adversaries may attempt to extract credential material from the Security Account Manager (SAM) database either through in-memory techniques or through the Windows Registry where the SAM database is stored.
attack.mitre.org →
T1003.003 NTDS Credential Access
Adversaries may attempt to access or create a copy of the Active Directory domain database in order to steal credential information, as well as obtain other information about domain members such as devices, users, and access rights.
attack.mitre.org →
T1010 Application Window Discovery Discovery
Adversaries may attempt to get a listing of open application windows.
attack.mitre.org →
T1014 Rootkit Stealth
Adversaries may use rootkits to hide the presence of programs, files, network connections, services, drivers, and other system components.
attack.mitre.org →
Derived from this CVE’s CWE(s) via the direct CWE→ATT&CK cross-walk.

CVEs Like This One

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CVE-2026-55949Same product: Microsoft 365 Apps
CVE-2026-97011Same product: Microsoft 365 Apps
CVE-2026-78519Same product: Microsoft 365 Apps
CVE-2024-49029Same product: Microsoft 365 Apps
CVE-2025-53759Same product: Microsoft 365 Apps
CVE-2025-21357Same product: Microsoft 365 Apps
CVE-2026-40422Same vendor: Microsoft
CVE-2025-53799Same vendor: Microsoft
CVE-2025-50156Same vendor: Microsoft

Affected Assets

microsoft
365 apps
all versions
microsoft
microsoft 365
all versions
microsoft
office 2021
all versions
microsoft
office 2024
all versions

Mitigating Controls

Mitigating Controls (NIST 800-53 r5) AI

SA-11 Developer Testing and Evaluation partial match

Developer testing and evaluation (including static analysis) can find uses of uninitialized resources after they are coded.

SA-15 Development Process, Standards, and Tools partial match

Requiring documented development standards and tools can mandate initialization checks and safe patterns that stop the weakness from being introduced.

SA-8 Security and Privacy Engineering Principles partial match

Engineering principles can require explicit resource initialization before use, structurally avoiding uninitialized access.

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 partial match
blocks

Secure SDLC activities such as static analysis and code review directly prevent use of uninitialized resources while also addressing many other weaknesses.

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.5.14 Information transfer partial match
removes
A.5.15 Access control partial match
removes
A.5.16 Identity management partial match
removes
A.5.17 Authentication information partial match
removes
A.5.18 Access rights partial match
removes
A.8.10 Information deletion partial match
removes

References