EUVD-2026-56698
GHSA-7phx-8ch5-hmfm
Severity by source
AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
Local file-parse trigger with no attacker privileges needed; user must open the file; full code execution yields complete CIA impact with unchanged scope.
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
Integer overflow or wraparound in Microsoft Office allows an unauthorized attacker to execute code locally.
AnalysisAI
Local code execution in Microsoft Office results from an integer overflow that leads to a heap-based buffer overflow (CWE-122), enabling an attacker to run arbitrary code at the privilege level of the logged-in user. Affected products span multiple Windows and Mac release tracks including Office 2016, 2019, LTSC 2021, LTSC 2024, and Microsoft 365 Apps for Enterprise. …
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Attack ChainAIDerived
Hypothetical attack flow derived from CVE metadata
Vulnerability AssessmentAI
| Exploitation | The victim must open a crafted Microsoft Office document using an affected version of Office on Windows or macOS - this is the sole required precondition, as the CVSS vector specifies PR:N (no attacker privileges) and UI:R (victim must interact with the file). … Additional conditions and limiting factors are described in the full assessment. |
| Risk Assessment | The CVSS 7.8 High score is driven by complete confidentiality, integrity, and availability impact (C:H/I:H/A:H) with a local attack vector and low complexity - a combination that accurately reflects the severity of arbitrary code execution. … Full risk analysis with EPSS, KEV, and SSVC signal comparison available after sign-in. |
| Exploit Scenario | An attacker crafts a malicious Office document (e.g., a Word or Excel file) embedding a record with a size field engineered to trigger an integer overflow during parsing, causing a heap buffer smaller than the subsequent write. The file is delivered via phishing email or a compromised download link. … |
| Remediation | Apply the vendor-released patch immediately. … Detailed patch versions, workarounds, and compensating controls in full report. |
Recommended ActionAI
Within 24 hours, distribute a security alert to all stakeholders and create a definitive inventory of Microsoft Office deployments across Windows and macOS systems, identifying which devices run Office 2016, 2019, LTSC 2021, LTSC 2024, or Microsoft 365 Apps for Enterprise. …
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Same weakness CWE-122 – Heap-based Buffer Overflow
View allSame technique Heap Overflow
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External POC / Exploit Code
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