EUVD-2026-44213
GHSA-mpf7-wp9r-5pwf
Severity by source
AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
File-open vector so AV:L and UI:R; no auth needed (PR:N); low complexity for a crafted document; code runs in user context yielding full C/I/A 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
2DescriptionCVE.org
Heap-based buffer overflow in Microsoft Office allows an unauthorized attacker to execute code locally.
AnalysisAI
Local code execution in Microsoft Office (2016, 2019, LTSC 2021/2024, 365 Apps for Enterprise, and Office for Mac) arises from a heap-based buffer overflow (CWE-122) that an attacker triggers by getting a victim to open a maliciously crafted Office document. Rated CVSS 7.8 with high impact to confidentiality, integrity, and availability, exploitation requires user interaction but no prior authentication or privileges. …
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Attack ChainAIDerived
Hypothetical attack flow derived from CVE metadata
Vulnerability AssessmentAI
| Exploitation | Exploitation requires the victim to open a specially crafted Microsoft Office document in a vulnerable Office edition (PR:N, UI:R) - the document itself is the delivery mechanism, so the exploit succeeds against default Office configurations with no special feature toggle needed, but it will NOT fire without that user action. … Additional conditions and limiting factors are described in the full assessment. |
| Risk Assessment | The CVSS 3.1 vector (AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H, base 7.8) describes a file-borne local vector: no privileges are needed (PR:N) but the victim must open a malicious document (UI:R), and successful exploitation yields full high impact on the host in the user's context. … Full risk analysis with EPSS, KEV, and SSVC signal comparison available after sign-in. |
| Exploit Scenario | An attacker emails a booby-trapped Office document (or hosts it on a share or website) to a target and, through social engineering, persuades the user to open it. When Office parses the crafted file, the heap-based buffer overflow is triggered and the attacker's shellcode runs with the privileges of the logged-in user, giving foothold for data theft or further compromise. … |
| Remediation | Patch available per vendor advisory - apply the Microsoft security update for CVE-2026-55140 documented at https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-55140, selecting the fixed build for your specific channel (Current, Monthly Enterprise, or Semi-Annual for 365 Apps; the LTSC servicing updates for 2016/2019/2021/2024; and the corresponding macOS updates). … Detailed patch versions, workarounds, and compensating controls in full report. |
Recommended ActionAI
Within 24 hours: Inventory Microsoft Office deployments (2016, 2019, LTSC 2021/2024, 365 Apps for Enterprise, Mac) organization-wide and issue security awareness communication advising users to avoid opening documents from untrusted sources. …
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Local code execution in Microsoft Word (and Office/SharePoint components that render Word content) stems from an integer
Local code execution in Microsoft Office (2016, 2019, LTSC 2021/2024, Microsoft 365 Apps, and the macOS editions) arises
Arbitrary code execution in Microsoft Office Word (and the broader Office/365/SharePoint family) arises from a stack-bas
Local code execution in Microsoft Office (including Microsoft 365 Apps for Enterprise, Office 2016/2019, and Office LTSC
Local code execution in Microsoft Word (part of Microsoft 365 Apps, Office 2019, Office LTSC 2021/2024, and Office for M
Local arbitrary code execution in Microsoft Office (2016, 2019, LTSC 2021/2024, Microsoft 365 Apps for Enterprise, and O
Arbitrary code execution in Microsoft PowerPoint (and the broader Microsoft Office/365 suite on Windows and macOS) arise
Local code execution in Microsoft Office PowerPoint (including Microsoft 365 Apps, Office 2019, Office LTSC 2021/2024, a
Local code execution in Microsoft Office PowerPoint (CWE-122 heap-based buffer overflow) lets an unauthorized attacker r
Local code execution in Microsoft Word (and the wider Microsoft Office / Microsoft 365 Apps family) lets an unauthorized
Local code execution in Microsoft Office (2016, 2019, LTSC 2021/2024, Microsoft 365 Apps for Enterprise, and Office for
Local code execution in Microsoft Office (2016, 2019, LTSC 2021/2024, Microsoft 365 Apps, and Office for Mac 2021/2024)
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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