Jul 2026: Microsoft Excel Remote Code Execution Vulnerability
CVE-2026-55048 Published on July 14, 2026

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

Vendor Advisory NVD

Weakness Types

Integer Overflow or Wraparound

The software performs a calculation that can produce an integer overflow or wraparound, when the logic assumes that the resulting value will always be larger than the original value. This can introduce other weaknesses when the calculation is used for resource management or execution control. An integer overflow or wraparound occurs when an integer value is incremented to a value that is too large to store in the associated representation. When this occurs, the value may wrap to become a very small or negative number. While this may be intended behavior in circumstances that rely on wrapping, it can have security consequences if the wrap is unexpected. This is especially the case if the integer overflow can be triggered using user-supplied inputs. This becomes security-critical when the result is used to control looping, make a security decision, or determine the offset or size in behaviors such as memory allocation, copying, concatenation, etc.

Heap-based Buffer Overflow

A heap overflow condition is a buffer overflow, where the buffer that can be overwritten is allocated in the heap portion of memory, generally meaning that the buffer was allocated using a routine such as malloc().


Products Associated with CVE-2026-55048

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Microsoft Office 2021
 
Microsoft Office 2019
 
Microsoft 365 Apps
 
Microsoft Office Macos 2021
 
Microsoft Office 2024
 
Microsoft Office Macos 2024
 
Microsoft Excel 2016
 
Microsoft Office 365
 

Affected Versions

Microsoft 365 Apps for Enterprise: Microsoft Excel 2016: Microsoft Office 2019: Microsoft Office 365 for Mac: Microsoft Office LTSC 2021: Microsoft Office LTSC 2024: Microsoft Office LTSC for Mac 2021: Microsoft Office LTSC for Mac 2024: Microsoft Office Online Server: