EUVD-2026-44191
GHSA-6236-c2c5-2j6c
Severity by source
AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
File must be opened locally by a user (AV:L, UI:R) with no prior auth (PR:N); successful overflow yields full code execution in user context, so C/I/A all High.
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 Excel allows an unauthorized attacker to execute code locally.
AnalysisAI
Local code execution in Microsoft Excel (and the broader Office 2016/2019/LTSC 2021/2024, Microsoft 365 Apps, Office for Mac, and Office Online Server family) results from a stack-based buffer overflow triggered when a victim opens a maliciously crafted spreadsheet. An attacker who convinces a user to open a booby-trapped file can run arbitrary code in the context of that user, with full confidentiality, integrity, and availability impact. …
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Attack ChainAIDerived
Hypothetical attack flow derived from CVE metadata
Vulnerability AssessmentAI
| Exploitation | Exploitation requires the victim to open an attacker-supplied malicious Excel/Office document on the local machine (UI:R - user interaction is mandatory), which is the concrete prerequisite that limits this flaw. … Additional conditions and limiting factors are described in the full assessment. |
| Risk Assessment | The CVSS 3.1 base score is 7.8 (High) with vector AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H - although PR:N indicates no prior authentication, the AV:L and UI:R metrics show this is not a remotely automatable attack: it requires a local file to be opened by a user, so it behaves like a client-side, social-engineering-dependent flaw rather than a wormable network bug. … Full risk analysis with EPSS, KEV, and SSVC signal comparison available after sign-in. |
| Exploit Scenario | An attacker emails a finance employee a spreadsheet disguised as an invoice or report; when the victim opens it and dismisses or bypasses Protected View, the crafted content overflows a stack buffer in Excel's parser and executes attacker code as that user. Because AV:L and UI:R apply, success hinges on social engineering rather than a network exploit, and no public exploit is identified at time of analysis. |
| Remediation | Patch available per vendor advisory - apply Microsoft's security update for CVE-2026-55141 via the MSRC Update Guide at https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-55141, ensuring updates reach every channel in use (Microsoft 365 Apps, Office 2016/2019, LTSC 2021/2024, Office for Mac, and Office Online Server), since the same flaw spans all of them. … Detailed patch versions, workarounds, and compensating controls in full report. |
Recommended ActionAI
Within 24 hours, verify patch availability through Microsoft security advisories and confirm current Office version inventory across your organization (2016, 2019, LTSC 2021, 2024, Microsoft 365 Apps, Office for Mac, and Office Online Server). …
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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-121 – Stack-based Buffer Overflow
View allSame technique Buffer Overflow
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External POC / Exploit Code
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