EUVD-2026-73855
GHSA-g485-2f9g-56cp
Severity by source
AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
File-parsing attack requires local execution via user opening a malicious document; no system privileges needed, but UI:R is mandatory.
Primary rating from Vendor (microsoft).
CVSS VectorVendor: microsoft
Lifecycle Timeline
3DescriptionCVE.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 when a victim opens a specially crafted Excel file. Affected products span nearly every current Office release line - Excel 2016, Office 2019, Office LTSC 2021 and 2024 (Windows and Mac), Microsoft 365 Apps for Enterprise, Office 365 for Mac, and Office Online Server. …
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Attack ChainAIDerived
Hypothetical attack flow derived from CVE metadata
Vulnerability AssessmentAI
| Exploitation | The victim must open a specially crafted Excel file using an affected version of Microsoft Excel. … Additional conditions and limiting factors are described in the full assessment. |
| Risk Assessment | CVSS 7.8 (AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H) correctly reflects the local-execution-via-malicious-file model. … Full risk analysis with EPSS, KEV, and SSVC signal comparison available after sign-in. |
| Exploit Scenario | Full exploit scenario with step-by-step reproduction available after sign-in. |
| Remediation | Apply Microsoft's patch via Windows Update, Microsoft Update Catalog, or the Microsoft 365 Apps update channel as applicable to your deployment. … Detailed patch versions, workarounds, and compensating controls in full report. |
Recommended ActionAI
Within 24 hours, inventory all systems running affected Excel versions (Excel 2016, Office 2019, Office LTSC 2021/2024, Microsoft 365 Apps for Enterprise, Office 365 for Mac, Office Online Server) and issue guidance to users to avoid opening Excel files from untrusted sources. …
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Same weakness CWE-122 – Heap-based Buffer Overflow
View allSame technique Buffer Overflow
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External POC / Exploit Code
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