ReviewHigh

CVE-2026-70329

Microsoft Microsoft 365 Apps for Enterprise, Microsoft Office 2019, Microsoft Office LTSC 2021

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

PRIORITY ASSESSMENT

The CVSS severity warrants an early asset and exposure review.

Known exploitationNot established by KEV

Exploit probability-

Technical severityCVSS 8.8

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

Product: Microsoft Microsoft 365 Apps for Enterprise, Microsoft Office 2019, Microsoft Office LTSC 2021
Affected versions: >= 16.0.1 < https://aka.ms/OfficeSecurityReleases, >= 19.0.0 < https://aka.ms/OfficeSecurityReleases, >= 16.0.0 < https://aka.ms/OfficeSecurityReleases, >= 16.0.0.0 < 16.0.5565.1000, 2016
Fixed versions: No verified fixed-version field is available yet

Confirm exposure before applying a vendor-supported change.

1
Identify
Confirm that Microsoft Microsoft 365 Apps for Enterprise, Microsoft Office 2019, Microsoft Office LTSC 2021 and an affected version are present.
2
Prioritize
Combine exploitation signals with asset exposure and business criticality.
3
Remediate
Follow the vendor advisory or supported update path and preserve rollback options.
4
Verify
Recheck the version, service health, access paths, and relevant logs.