CVE-2026-83891

Analyzed Analyzed - Analysis Complete

Microsoft Office Word Stack-Based Buffer Overflow

Publication date: 2026-10-13

Last updated on: 2026-10-15

Assigner: Microsoft Corporation

Description

Stack-based buffer overflow in Microsoft Office Word allows an unauthorized attacker to execute code over a network.

CVSS Scores

EPSS Scores

Probability:
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Meta Information

Published

2026-10-13

Last Modified

2026-10-15

Generated

2026-10-19

AI Q&A

2026-10-14

EPSS Evaluated

2026-10-18

NVD

CVE-2026-83891

EUVD

EUVD-2026-99721

Affected Vendors & Products

Vendor	Product	Version / Range
microsoft	365_apps	*
microsoft	365_apps	*
microsoft	microsoft_365	*
microsoft	office_2021	*
microsoft	office_2021	*
microsoft	office_2021	*
microsoft	office_2024	*
microsoft	office_2024	*
microsoft	office_2024	*

Helpful Resources

Exploitability

CWE

KEV

CWE ID	Description
CWE-121	A stack-based buffer overflow condition is a condition where the buffer being overwritten is allocated on the stack (i.e., is a local variable or, rarely, a parameter to a function).
CWE-20	The product receives input or data, but it does not validate or incorrectly validates that the input has the properties that are required to process the data safely and correctly.

Attack-Flow Graph

Executive Summary

This is a stack-based buffer overflow vulnerability in Microsoft Office Word. It allows an unauthorized attacker to execute arbitrary code remotely over a network by exploiting a flaw in how Word handles certain data.

Detection Guidance

Detection typically involves monitoring for unusual behavior in Microsoft Office Word processes, such as crashes or unexpected network activity. Use tools like Microsoft Defender for Endpoint to scan for exploits targeting this vulnerability. Check for updates from Microsoft to ensure systems are patched.

Impact Analysis

An attacker could exploit this to run malicious code on your system, potentially stealing data, installing malware, or taking control of your computer. It requires user interaction, such as opening a specially crafted file.

Compliance Impact

This vulnerability allows remote code execution via a stack-based buffer overflow in Microsoft Office Word. Such vulnerabilities can lead to unauthorized access to sensitive data, which may violate GDPR's data protection requirements and HIPAA's safeguards for protected health information.

Mitigation Strategies

Apply the latest security updates from Microsoft for Office Word as soon as they become available to patch the stack-based buffer overflow vulnerability.

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