What’s Vulnerable › Vulnerabilities

CVE-2026-26144: Microsoft Excel Information Disclosure Vulnerability

• Severity: medium (CVSS 4.7 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 1.2% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-03-10 · updated 2026-06-19
• Weakness: CWE-79

Description

Improper neutralization of input during web page generation ('cross-site scripting') in Microsoft Office Excel allows an unauthorized attacker to disclose information over a network.

Affected products

• Microsoft 365 Apps: all versions
• Microsoft 365 Apps: from 16.0.1 before https://aka.ms/OfficeSecurityReleases — fixed in https://aka.ms/OfficeSecurityReleases

How to fix

Upgrade to a fixed version: Microsoft 365 Apps https://aka.ms/OfficeSecurityReleases. Check the vendor advisory for mitigations.

References

• https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-26144

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