CVE-2026-88166
Analyzed Analyzed - Analysis Complete

Integer Overflow in Microsoft Office SharePoint

Vulnerability report for CVE-2026-88166, including description, CVSS score, EPSS score, affected products, exploitability, helpful resources, and attack-flow context.

Publication date: 2026-10-13

Last updated on: 2026-10-14

Assigner: Microsoft Corporation

Description

Integer overflow or wraparound in Microsoft Office SharePoint allows an authorized attacker to execute code over a network.

CVSS Scores

EPSS Scores

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Meta Information

Published
2026-10-13
Last Modified
2026-10-14
Generated
2026-10-19
AI Q&A
2026-10-14
EPSS Evaluated
2026-10-18
NVD
EUVD

Affected Vendors & Products

Showing 1 associated CPE
Vendor Product Version / Range
microsoft sharepoint_server to 16.0.20326.20190 (exc)

Helpful Resources

Exploitability

CWE
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KEV
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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-190 The product performs a calculation that can produce an integer overflow or wraparound when the logic assumes that the resulting value will always be larger than the original value. This occurs when an integer value is incremented to a value that is too large to store in the associated representation. When this occurs, the value may become a very small or negative number.

Attack-Flow Graph

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Executive Summary

This vulnerability is an integer overflow or wraparound flaw in Microsoft Office SharePoint. An authorized attacker could exploit it to execute arbitrary code over a network by sending specially crafted input that triggers the overflow.

Impact Analysis

An attacker could gain control of a SharePoint server, leading to unauthorized code execution. This may allow data theft, system compromise, or further network infiltration if the server has elevated privileges.

Compliance Impact

This vulnerability could lead to unauthorized access or data breaches, violating GDPR (data protection) and HIPAA (health data privacy). Organizations may face fines, legal penalties, and reputational damage if exploited.

Mitigation Strategies

Apply the latest security updates from Microsoft for SharePoint Server to address the integer overflow issue. Monitor Microsoft's security advisories for patches and verify installation.

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