What’s Vulnerable › Vulnerabilities

CVE-2026-102858: Microsoft Office OneNote Remote Code Execution Vulnerability

• Severity: high (CVSS 8.8 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.9% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-10-13 · updated 2026-10-31
• Weakness: CWE-122

Description

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

Affected products

• Microsoft 365: all versions
• Microsoft Office 2021: all versions
• Microsoft Office LTSC 2024: all versions
• Microsoft Office 365 for Mac: from 1.0.0 before 16.114.26101123 — fixed in 16.114.26101123
• Microsoft Office LTSC for Mac 2024: from 16.0.0 before 16.114.26101123 — fixed in 16.114.26101123
• Microsoft Office LTSC for Mac 2021: from 16.0.1 before 16.114.26101123 — fixed in 16.114.26101123

How to fix

Upgrade to a fixed version: Microsoft Office 365 for Mac 16.114.26101123; Microsoft Office LTSC for Mac 2024 16.114.26101123; Microsoft Office LTSC for Mac 2021 16.114.26101123. Check the vendor advisory for mitigations.

References

• https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-102858

Get alerted when CVE-2026-102858 or the next vulnerability affects your stack