EUVD-2026-44158
GHSA-v986-mp4g-45cw
Severity by source
AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
File must be opened by a user (AV:L/UI:R) with no attacker privileges (PR:N); code runs in-process yielding full C/I/A impact within the user's 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
2DescriptionCVE.org
Heap-based buffer overflow in Microsoft Office allows an unauthorized attacker to execute code locally.
AnalysisAI
Local code execution in Microsoft Office (365 Apps for Enterprise, Office 2016/2019, and Office LTSC 2021/2024) arises from a heap-based buffer overflow that an attacker triggers when a victim opens a maliciously crafted Office document. Successful exploitation yields full confidentiality, integrity, and availability impact in the context of the current user. …
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Attack ChainAIDerived
Hypothetical attack flow derived from CVE metadata
Vulnerability AssessmentAI
| Exploitation | Exploitation requires a user to open or preview an attacker-crafted Office file in a vulnerable Office build (Microsoft 365 Apps, Office 2016/2019, or Office LTSC 2021/2024); the CVSS UI:R metric confirms victim interaction is mandatory, which is the key limiting factor. … Additional conditions and limiting factors are described in the full assessment. |
| Risk Assessment | The CVSS 3.1 base score of 7.8 (AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H) describes a local vector requiring user interaction but no privileges, with high impact across all three security properties - the classic 'open a malicious document' profile. … Full risk analysis with EPSS, KEV, and SSVC signal comparison available after sign-in. |
| Exploit Scenario | An attacker emails a victim a crafted Office document (e.g., via a phishing lure) that, when opened, overflows a heap buffer in Office's file parser and executes attacker code with the victim's privileges. Because the vector is local with required user interaction (AV:L/UI:R), the attack hinges on social engineering to get the file opened rather than any remote network exposure. … |
| Remediation | Patch available per vendor advisory: apply the Microsoft security update for CVE-2026-55017 detailed at https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-55017, ensuring Click-to-Run channels (Microsoft 365 Apps) auto-update and that MSI-based Office 2016/2019 and LTSC 2021/2024 installations receive the corresponding monthly update. … Detailed patch versions, workarounds, and compensating controls in full report. |
Recommended ActionAI
Within 24 hours, conduct an inventory of all Microsoft Office deployments (365 Apps for Enterprise, Office 2016/2019, Office LTSC 2021/2024) and brief end-users on patch urgency and document-opening risks. …
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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-122 – Heap-based Buffer Overflow
View allSame technique Heap Overflow
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External POC / Exploit Code
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