Jun 2026: Microsoft Excel Remote Code Execution Vulnerability: CVE-2026-44823 June 2026

Jun 2026: Microsoft Excel Remote Code Execution Vulnerability
CVE-2026-44823 Published on June 9, 2026

Microsoft Excel Remote Code Execution Vulnerability
Integer underflow (wrap or wraparound) in Microsoft Office Excel allows an unauthorized attacker to execute code locally.

Weakness Types

Numeric Truncation Error

Truncation errors occur when a primitive is cast to a primitive of a smaller size and data is lost in the conversion. When a primitive is cast to a smaller primitive, the high order bits of the large value are lost in the conversion, potentially resulting in an unexpected value that is not equal to the original value. This value may be required as an index into a buffer, a loop iterator, or simply necessary state data. In any case, the value cannot be trusted and the system will be in an undefined state. While this method may be employed viably to isolate the low bits of a value, this usage is rare, and truncation usually implies that an implementation error has occurred.

What is a Dangling pointer Vulnerability?

Referencing memory after it has been freed can cause a program to crash, use unexpected values, or execute code.

CVE-2026-44823 has been classified to as a Dangling pointer vulnerability or weakness.

Products Associated with CVE-2026-44823

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Affected Versions

Version 16.0.1 and below https://aka.ms/OfficeSecurityReleases is affected.

Version 16.0.0.0 and below 16.0.5556.1001 is affected.

Version 19.0.0 and below https://aka.ms/OfficeSecurityReleases is affected.

Version - is affected.