What’s Vulnerable › Vulnerabilities

CVE-2026-20949: Microsoft Excel Security Feature Bypass Vulnerability

• Severity: high (CVSS 7.8 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.5% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-01-13 · updated 2026-07-30
• Weakness: CWE-284

Description

Improper access control in Microsoft Office Excel allows an unauthorized attacker to bypass a security feature locally.

Affected products

• Microsoft 365 Apps: all versions
• Microsoft Office LTSC for Mac 2021: 2021, 2024
• 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 https://aka.ms/OfficeSecurityReleases — fixed in https://aka.ms/OfficeSecurityReleases
• Microsoft Office LTSC for Mac 2024: from 16.0.0 before 16.105.26011018 — fixed in 16.105.26011018
• Microsoft Office LTSC 2024: from 16.0.0 before https://aka.ms/OfficeSecurityReleases — fixed in https://aka.ms/OfficeSecurityReleases
• Microsoft Office LTSC for Mac 2021: from 16.0.1 before 16.105.26011018 — fixed in 16.105.26011018

How to fix

Upgrade to a fixed version: Microsoft 365 Apps https://aka.ms/OfficeSecurityReleases; Microsoft Office LTSC 2021 https://aka.ms/OfficeSecurityReleases; Microsoft Office LTSC for Mac 2024 16.105.26011018; Microsoft Office LTSC 2024 https://aka.ms/OfficeSecurityReleases; Microsoft Office LTSC for Mac 2021 16.105.26011018. Check the vendor advisory for mitigations.

References

• https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-20949

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