What is the CVSS score of CVE-2026-68815?

CVE-2026-68815 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: 0.3%.

Which versions of Microsoft Excel are affected by CVE-2026-68815?

Microsoft Office Excel contains a vulnerability enabling local code execution (CVSS 7.8, CVE-2026-68815) when users open malicious files, exposing any organization with Excel deployments to system…. A patch is available.

How to fix or mitigate CVE-2026-68815?

Within 24 hours, conduct an inventory of all Excel installations across the enterprise, identify business-critical systems and users, and distribute security awareness communication warning employees against opening untrusted spreadsheet files from external sources. Within 7 days, deploy mitigating technical controls including disabling Excel 4.0 macros and VBA macro execution via Group Policy or Microsoft Intune, enabling Microsoft Defender Attack Surface Reduction rules for Office application processes, and restricting file transfer mechanisms including email and shared drive access for Excel documents. Within 30 days, establish patch management coordination with Microsoft, evaluate application control policies to restrict Excel execution to trusted paths, assess feasibility of transitioning non-critical workflows to alternative spreadsheet platforms, and implement user awareness training focused on social engineering tactics delivering malicious spreadsheets.

Microsoft Excel CVE-2026-68815

EUVD-2026-56465 HIGH

Heap-based Buffer Overflow (CWE-122)

2026-08-11 secure@microsoft.com

GHSA-9223-7x8q-h7rv

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

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

File-based local attack requires no attacker privileges (PR:N) but mandates user interaction (UI:R); full C/I/A impact reflects arbitrary code execution in user context.

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

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

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 - 18:01 vuln.today

CVE Published

Aug 11, 2026 - 17:19 nvd

HIGH 7.8

DescriptionCVE.org

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

AnalysisAI

Heap-based buffer overflow in Microsoft Office Excel enables local code execution with full system-level impact when a victim opens a specially crafted Excel file. The flaw (CWE-122) resides in Excel's file parsing logic, where malformed input causes a heap memory region to be overwritten, redirecting execution flow. …

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Attack ChainAIDerived

Hypothetical attack flow derived from CVE metadata

Access

Craft malicious Excel file with malformed heap-overflow payload

Delivery

Deliver file via phishing email or social engineering

Exploit

Victim opens file, bypassing Protected View

Execution

Excel parser processes malformed record, overflowing heap buffer

Persist

Attacker-controlled code executes in victim user context

Impact

Post-exploitation activity (credential theft, persistence, lateral movement)

Access

Craft malicious Excel file with malformed heap-overflow payload

Delivery

Deliver file via phishing email or social engineering

Exploit

Victim opens file, bypassing Protected View

Execution

Excel parser processes malformed record, overflowing heap buffer

Persist

Attacker-controlled code executes in victim user context

Impact

Post-exploitation activity (credential theft, persistence, lateral movement)

Vulnerability AssessmentAI

Exploitation	Exploitation requires a victim to open a specially crafted Excel file on a local system running a vulnerable version of Microsoft Office Excel. … Additional conditions and limiting factors are described in the full assessment.
Risk Assessment	The CVSS base score of 7.8 (High) reflects a locally-triggered, high-impact vulnerability with low attack complexity. … Full risk analysis with EPSS, KEV, and SSVC signal comparison available after sign-in.
Exploit Scenario	An attacker crafts a malicious Excel workbook containing a purposely malformed record structure that triggers the heap buffer overflow when Excel's parser processes the file. The file is delivered to a targeted employee via a phishing email or shared link. …
Remediation	Apply the Microsoft security update addressing CVE-2026-68815, available through the Microsoft Update Catalog and Windows Update via the MSRC advisory at https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-68815. … Detailed patch versions, workarounds, and compensating controls in full report.

Recommended ActionAI

Within 24 hours, conduct an inventory of all Excel installations across the enterprise, identify business-critical systems and users, and distribute security awareness communication warning employees against opening untrusted spreadsheet files from external sources. …

Threat intelligence, references, and detailed analysis are available after sign-in.