Microsoft Office Excel heap-based overflow

Summaryinfo

A vulnerability identified as problematic has been detected in Microsoft Office. This vulnerability affects unknown code of the component Excel. The manipulation leads to heap-based overflow. This vulnerability is documented as CVE-2026-55029. The attack needs to be performed locally. There is not any exploit available.

Detailsinfo

A vulnerability, which was classified as problematic, has been found in Microsoft Office (affected version not known). This issue affects some unknown functionality of the component Excel. The manipulation with an unknown input leads to a heap-based overflow vulnerability. Using CWE to declare the problem leads to CWE-122. 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(). Impacted is confidentiality, integrity, and availability. The summary by CVE is:

Heap-based buffer overflow in Microsoft Office Excel allows an unauthorized attacker to execute code locally.

The advisory is shared at msrc.microsoft.com. The identification of this vulnerability is CVE-2026-55029 since 06/16/2026. The exploitation is known to be easy. An attack has to be approached locally. It demands that the victim is doing some kind of user interaction. Neither technical details nor an exploit are publicly available. The price for an exploit might be around USD $5k-$25k at the moment (estimation calculated on 07/14/2026).

There is no information about possible countermeasures known. It may be suggested to replace the affected object with an alternative product.

If you want to get the best quality for vulnerability data then you always have to consider VulDB.

Productinfo

Type

• Office Suite Software

Vendor

• Microsoft

Name

• Office

License

• commercial

Website

• Vendor: https://www.microsoft.com/

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