EUVD-2026-56759
GHSA-hv7j-5cx9-87r4
Severity by source
AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
File-borne attack requires no system privileges (PR:N) but mandates user opens the file (UI:R, AV:L); successful heap overflow yields full code execution impact.
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
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 user opens a specially crafted Excel file. The CVSS vector (AV:L/PR:N/UI:R) confirms the attack requires no system privileges but does require user interaction - the classic malicious-document delivery pattern. …
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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 in an affected version of Microsoft Excel - this is the sole triggering condition confirmed by the CVSS UI:R metric. … Additional conditions and limiting factors are described in the full assessment. |
| Risk Assessment | The CVSS base score of 7.8 (High) is well-calibrated for this class of vulnerability. … Full risk analysis with EPSS, KEV, and SSVC signal comparison available after sign-in. |
| Exploit Scenario | An attacker crafts a malicious Excel workbook (.xls or .xlsx) that triggers a heap-based buffer overflow in Excel's file parser upon opening. The file is delivered to a target employee via a phishing email or shared link, and when the employee opens it in Microsoft Excel, the overflow corrupts heap memory, redirecting execution to attacker-controlled shellcode or ROP chain. … |
| Remediation | The primary remediation is to apply the vendor-supplied patch via Microsoft's standard update channels (Windows Update, Microsoft Update Catalog, or Microsoft 365 update mechanism). … Detailed patch versions, workarounds, and compensating controls in full report. |
Recommended ActionAI
Within 24 hours, issue urgent security communication to all staff warning against opening Excel files from untrusted sources and disable macros in Excel application settings. …
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Same weakness CWE-122 – Heap-based Buffer Overflow
View allSame technique Heap Overflow
View allShare
External POC / Exploit Code
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