EUVD-2026-44200
GHSA-x639-3674-v6hc
Severity by source
AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
Malicious file must be opened locally (AV:L, UI:R) with no prior auth (PR:N); memory-corruption RCE gives full C/I/A in the user's process (scope unchanged).
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
Stack-based buffer overflow in Microsoft Office Word allows an unauthorized attacker to execute code locally.
AnalysisAI
Arbitrary code execution in Microsoft Office Word (and the broader Office/365/SharePoint family) arises from a stack-based buffer overflow (CWE-121) that an attacker triggers when a victim opens a maliciously crafted document. The CVSS 3.1 vector (AV:L/UI:R) confirms this is a file-borne, local-context flaw requiring the user to open attacker-supplied content, yielding full confidentiality, integrity, and availability impact in the user's session. …
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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 Word document (CVSS UI:R), so the limiting factor is user interaction - the attack cannot succeed without a user opening attacker-supplied content, and there is no remote unauthenticated path against a default client. … Additional conditions and limiting factors are described in the full assessment. |
| Risk Assessment | The signals are moderate-but-actionable. … Full risk analysis with EPSS, KEV, and SSVC signal comparison available after sign-in. |
| Exploit Scenario | An attacker crafts a malicious Word document that overflows a stack buffer during parsing and emails or shares it with a target; when the victim opens the file, the overflow redirects execution and runs attacker code in the context of the user. Because UI:R is required, the attack relies on social engineering to get the document opened, and no public exploit code is currently identified. |
| Remediation | Patch available per vendor advisory - apply Microsoft's security update for each affected channel as documented at https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-55038 (exact fixed build numbers are not included in the provided data and should be taken from that MSRC page). … Detailed patch versions, workarounds, and compensating controls in full report. |
Recommended ActionAI
Within 24 hours, inventory all Microsoft Office and Office 365 installations across the organization and classify by user criticality; verify the latest MSRC patch is available in your patch management system and stage for deployment. …
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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
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)
Local code execution in Microsoft Word (Office 2016/2019, Microsoft 365 Apps, Office LTSC 2021/2024) arises from a heap-
Same weakness CWE-121 – Stack-based Buffer Overflow
View allSame technique Buffer Overflow
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External POC / Exploit Code
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