What’s Vulnerable › Vulnerabilities

CVE-2026-88195: Microsoft Office Excel Information Disclosure Vulnerability

• Severity: medium (CVSS 6.5 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.8% 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-126

Description

Buffer over-read in Microsoft Office Excel allows an unauthorized attacker to disclose information over a network.

Affected products

• Microsoft 365 Apps: 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 LTSC 2021: from 16.0.1 before 16.0.14334.20974 — fixed in 16.0.14334.20974
• Microsoft Office LTSC 2024: from 16.0.0 before 16.0.17932.21056 — fixed in 16.0.17932.21056

How to fix

Upgrade to a fixed version: Microsoft 365 Apps https://aka.ms/OfficeSecurityReleases; Microsoft Office LTSC 2021 16.0.14334.20974; Microsoft Office LTSC 2024 16.0.17932.21056. Check the vendor advisory for mitigations.

References

• https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-88195

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