Jul 2026: Microsoft Excel Remote Code Execution Vulnerability
CVE-2026-55899 Published on July 14, 2026
Microsoft Excel Remote Code Execution Vulnerability
Stack-based buffer overflow in Microsoft Office Excel allows an unauthorized attacker to execute code locally.
Weakness Types
What is a Stack Overflow Vulnerability?
A stack-based buffer overflow condition is a condition where the buffer being overwritten is allocated on the stack (i.e., is a local variable or, rarely, a parameter to a function).
CVE-2026-55899 has been classified to as a Stack Overflow vulnerability or weakness.
Improper Input Validation
The product receives input or data, but it does not validate or incorrectly validates that the input has the properties that are required to process the data safely and correctly.
Products Associated with CVE-2026-55899
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Affected Versions
Microsoft 365 Apps for Enterprise:- Version 16.0.1 and below https://aka.ms/OfficeSecurityReleases is affected.
- Version 16.0.0.0 and below 16.0.5561.1001 is affected.
- Version 19.0.0 and below https://aka.ms/OfficeSecurityReleases is affected.
- Version 1.0.0 and below 16.111.26071215 is affected.
- Version 16.0.1 and below https://aka.ms/OfficeSecurityReleases is affected.
- Version 16.0.0 and below https://aka.ms/OfficeSecurityReleases is affected.
- Version 16.0.1 and below 16.111.26071215 is affected.
- Version 16.0.0 and below 16.111.26071215 is affected.
- Version 16.0.0.0 and below 16.0.10417.20175 is affected.