What is the CVSS score of EUVD-2026-56762?

EUVD-2026-56762 has a CVSS 3.1 base score of 7.8 (High). CVSS vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H. EPSS exploitation probability: 0.4%.

Which versions of Microsoft Excel are affected by EUVD-2026-56762?

Microsoft Office Excel users are at risk from a HIGH-severity vulnerability (CVSS 7.8) that enables attackers to gain full system control when users open specially crafted files, potentially…. A patch is available.

How to fix or mitigate EUVD-2026-56762?

Within 24 hours, inventory all systems running Microsoft Office Excel across the organization, enable real-time endpoint monitoring for suspicious file handling, and issue a security alert to employees against opening Excel files from untrusted sources. Over the next 7 days, deploy detection signatures and file-blocking policies to restrict opening of suspicious Excel files, conduct a mandatory security awareness briefing on social engineering and file-based threats, and establish 24/7 incident response escalation procedures. Within 30 days, strengthen endpoint detection and response (EDR) capabilities to detect exploitation attempts, implement sandboxing or restricted execution for high-risk users, and establish automated monitoring of vendor security advisories to apply patches immediately upon release.

Microsoft Excel EUVD-2026-56762

| CVE-2026-68817 HIGH

Stack-based Buffer Overflow (CWE-121)

2026-08-11 secure@microsoft.com

GHSA-6mcr-3v92-fh29

Buffer Overflow Microsoft Stack Overflow 365 Apps Excel Microsoft 365 Office 2021 Office 2024 Office 2019

7.8

CVSS 3.1 · Vendor: microsoft

Severity by source

Vendor (microsoft) PRIMARY

7.8 HIGH

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

vuln.today AI

7.8 HIGH

Local file-open attack with no attacker privileges needed; mandatory user interaction; full CIA impact on the Excel process; no scope change beyond the vulnerable application.

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

4.0 AV:L/AC:L/AT:N/PR:N/UI:A/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N

Primary rating from Vendor (microsoft).

CVSS VectorVendor: microsoft

Attack Vector

Local

Attack Complexity

Low

Privileges Required

None

User Interaction

Required

Scope

Unchanged

Confidentiality

High

Integrity

High

Availability

High

Lifecycle Timeline

Patch available

Aug 11, 2026 - 18:19 EUVD

Analysis Generated

Aug 11, 2026 - 18:00 vuln.today

CVE Published

Aug 11, 2026 - 17:19 nvd

HIGH 7.8

DescriptionCVE.org

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

AnalysisAI

Stack-based buffer overflow in Microsoft Office Excel enables local arbitrary code execution when a user opens a specially crafted file. The vulnerability (CWE-121) carries a CVSS 7.8 High score, with high confidentiality, integrity, and availability impact upon successful exploitation. No active exploitation has been confirmed (not listed in CISA KEV), and no public exploit code is identified at time of analysis.

Technical ContextAI

CWE-121 (Stack-based Buffer Overflow) describes a condition where a program writes beyond the allocated stack buffer boundary, overwriting adjacent memory including return addresses or function pointers. In Microsoft Excel's context, this overflow is triggered during file parsing or processing of a maliciously crafted spreadsheet document. The CVSS vector (AV:L/AC:L/PR:N/UI:R) confirms the attack surface is local - consistent with Excel's document-handling code path - and requires no special privileges from the attacker, only that the victim interacts with a crafted file. No CPE strings were provided to identify the exact affected product versions or build ranges.

RemediationAI

Consult the Microsoft Security Response Center advisory at https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-68817 for the official patch. Apply all available Microsoft Office security updates via Windows Update or Microsoft Update Catalog. No exact patched version number was included in the available intelligence - patch version must be confirmed from the MSRC advisory before deploying. As a compensating control pending patching, configure Microsoft Office Protected View to open files from the internet and email attachments in read-only sandbox mode, which limits the ability of malicious files to execute code; note that users can manually dismiss Protected View, reducing its effectiveness. Additionally, consider enabling Attack Surface Reduction (ASR) rules in Microsoft Defender for Endpoint to block Office applications from creating child processes. Restricting macro execution and disabling Dynamic Data Exchange (DDE) where not operationally required further reduces the attack surface.