EUVD-2026-56422
GHSA-mvf6-42fg-9rcw
Severity by source
AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
AV:L reflects file-based triggering requiring local document open; UI:R because victim must open the crafted file; PR:N as the attacker needs no prior system access; full C/I/A impact consistent with arbitrary code execution.
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 Word allows an unauthorized attacker to execute code locally.
AnalysisAI
Heap-based buffer overflow in Microsoft Office Word enables arbitrary local code execution when a user opens a specially crafted document. The vulnerability spans a broad set of affected products across both Windows and macOS platforms, including Office LTSC 2021/2024, Office 2019, Microsoft 365 Apps for Enterprise, Office 365 for Mac, and Outlook 2016. …
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Attack ChainAIDerived
Hypothetical attack flow derived from CVE metadata
Vulnerability AssessmentAI
| Exploitation | Exploitation requires that the victim user actively opens a specially crafted Word document on a system running an affected version of Microsoft Office. … Additional conditions and limiting factors are described in the full assessment. |
| Risk Assessment | The CVSS 7.8 score and AV:L/UI:R vector accurately reflect that this is a file-opening-triggered exploit rather than a remotely exploitable service vulnerability - the attacker must deliver and convince the victim to open a malicious Word document. … Full risk analysis with EPSS, KEV, and SSVC signal comparison available after sign-in. |
| Exploit Scenario | An attacker crafts a malicious Word document embedding content designed to trigger the heap-based buffer overflow during document parsing. The document is delivered via a phishing email to a corporate user, who opens it in Microsoft Word. … |
| Remediation | Apply Microsoft's patch immediately via the standard Office update channel. … Detailed patch versions, workarounds, and compensating controls in full report. |
Recommended ActionAI
Within 24 hours, inventory all affected Office installations across the organization (Office LTSC 2021/2024, Office 2019, Microsoft 365 Apps for Enterprise, Office 365 for Mac, and Outlook 2016) and identify systems with the highest email exposure. …
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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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