CVE-2026-97743: Microsoft Office Excel Information Disclosure Vulnerability

Severity: medium (CVSS 6.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 1.0% 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-416

Description

Use after free in Microsoft Office Excel allows an unauthorized attacker to disclose information over a network.

Affected products

Microsoft 365 Apps: all versions
Microsoft 365: all versions
Microsoft Office 2021: all versions
Microsoft Office LTSC 2024: all versions
Microsoft 365 Apps: from 16.0.1 before https://aka.ms/OfficeSecurityReleases — fixed in https://aka.ms/OfficeSecurityReleases
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 365 Apps https://aka.ms/OfficeSecurityReleases; 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-2026-97743

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