CVE-2026-69734: Microsoft Office Word Information Disclosure Vulnerability

Severity: medium (CVSS 6.5 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: 2026-09-08 · updated 2026-10-14
Weakness: CWE-190

Description

Integer overflow or wraparound in Microsoft Office Word allows an unauthorized attacker to disclose information over a network.

Affected products

Microsoft 365 Apps: all versions
Microsoft 365: all versions
Microsoft Office 2016: all versions
Microsoft Office 2019: all versions
Microsoft Office 2021: all versions
Microsoft Office LTSC 2024: all versions
Microsoft Word for Android: 2016
Microsoft 365 Apps: from 16.0.1 before 16.0.20326.20138 — fixed in 16.0.20326.20138
Microsoft Office 365 for Mac: from 1.0.0 before 16.113.26091433 — fixed in 16.113.26091433
Microsoft Office LTSC 2021: from 16.0.1 before 16.0.14334.20906 — fixed in 16.0.14334.20906
Microsoft Office LTSC for Mac 2024: from 16.0.0 before 16.113.26091433 — fixed in 16.113.26091433
Microsoft Word 2016: from 16.0.1 before 16.0.5569.1003 — fixed in 16.0.5569.1003
Microsoft Office: from 16.0.0 before 16.0.5569.1000 — fixed in 16.0.5569.1000
Microsoft Office LTSC 2024: from 16.0.0 before 16.0.17932.20976 — fixed in 16.0.17932.20976
Microsoft Office LTSC for Mac 2021: from 16.0.1 before 16.113.26091433 — fixed in 16.113.26091433

How to fix

Upgrade to a fixed version: Microsoft 365 Apps 16.0.20326.20138; Microsoft Office 365 for Mac 16.113.26091433; Microsoft Office LTSC 2021 16.0.14334.20906; Microsoft Office LTSC for Mac 2024 16.113.26091433; Microsoft Word 2016 16.0.5569.1003; Microsoft Office 16.0.5569.1000; Microsoft Office LTSC 2024 16.0.17932.20976; Microsoft Office LTSC for Mac 2021 16.113.26091433. Check the vendor advisory for mitigations.

References

https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-69734

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