PT-2026-58534 · Microsoft · Office Excel

CVE-2026-55029 · Published 2026-07-14 · Updated 2026-07-15

Positive Technologies (AI Summary)

CVSS v3.1

7.8

High

Base vector

AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

Name of the Vulnerable Software and Affected Versions Microsoft Office Excel (affected versions not specified)

Description A heap-based buffer overflow exists in Microsoft Office Excel, which could allow an unauthorized attacker to execute arbitrary code locally. A heap-based buffer overflow occurs when a program writes more data to a heap memory buffer than it can hold, potentially corrupting memory and allowing for code execution.

Recommendations Install the July Office updates.

Fix

RCE

DoS

Heap Based Buffer Overflow

Weakness Enumeration

CWE-122

Related Identifiers

CVE-2026-55029

Affected Products

Office Excel

References · 4

• https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-55029 · Vendor Advisory
• http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2026-55029 · Security Note
• https://nvd.nist.gov/vuln/detail/CVE-2026-55029 · Security Note
• https://twitter.com/windowsforum/status/2077419457375252801 · Twitter Post