CVE-2026-56156 Details
Description
Heap-based buffer overflow in Microsoft Office Excel allows an unauthorized attacker to execute code locally.
A heap-based buffer overflow vulnerability has been identified in Microsoft Office Excel. This issue allows an unauthorized attacker to execute code locally. The vulnerability requires user interaction, as an attacker must send a malicious Office file and convince the user to open it. It is present in several editions of Microsoft Office, including Office LTSC 2024, Office LTSC 2021, Microsoft 365 Apps for Enterprise, and various versions for Mac.
Users can download the security update for their specific Office version through the Microsoft Update Catalog or via the Click-to-Run service. Instructions for applying these updates are available on the Microsoft Office Update Guidance page.
Metrics
CVSS 4.0 Severity and Vector Strings:
No CVSS 4.0 data is available for this CVE.
CVSS 3.x Severity and Vector Strings:
No data available for CVSS Version 2.0 on this CVE.
CISA-ADP
Assessed Jul 10, 2026References to Advisories, Solutions, and Tools
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| URL | Source(s) | Tag(s) |
|---|---|---|
| https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-56156 | [email protected] | Vendor Advisory |
Weakness Enumeration
| CWE-ID | CWE Name | Source |
|---|---|---|
| CWE-122 | Heap-based Buffer Overflow | [email protected] |
Affected Products
| Product | Versions |
|---|---|
| microsoft 365 apps | All versions |
CPE
Remediation
| |
| microsoft microsoft 365 | All versions |
CPE
Remediation
| |
| microsoft office 2021 | All versions |
CPE
Remediation
| |
| microsoft office 2024 | All versions |
CPE
Remediation
| |
Change History
4 change records found show changes
| Date | Action | Recorded By |
|---|---|---|
| Jul 15, 2026 | Initial Analysis | [email protected] |
| Jul 15, 2026 | CVE Modified | CISA-ADP |
| Jul 14, 2026 | CVE Modified | CISA-ADP |
| Jul 14, 2026 | New CVE Received | [email protected] |