EUVD-2026-44183
GHSA-8vvr-gcrm-9jm8
Severity by source
AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
Malicious file is parsed locally (AV:L) and needs the user to open it (UI:R) with no prior privileges (PR:N); memory-corruption RCE yields full C/I/A in 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 arbitrary code execution in Microsoft Office (Microsoft 365 Apps for Enterprise, Office 2016/2019, Office LTSC 2021/2024, and their macOS equivalents) arises from a heap-based buffer overflow (CWE-122) that an attacker triggers by convincing a user to open a maliciously crafted Office document. The CVSS 3.1 vector (AV:L/AC:L/PR:N/UI:R) shows the flaw requires user interaction but no prior privileges, yielding full high-impact compromise of confidentiality, integrity, and availability in the user's context. …
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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 Office document on a host running an affected Office build (AV:L with UI:R) - the file must be processed locally by the vulnerable parser. … Additional conditions and limiting factors are described in the full assessment. |
| Risk Assessment | This is a credible but interaction-gated priority. … Full risk analysis with EPSS, KEV, and SSVC signal comparison available after sign-in. |
| Exploit Scenario | An attacker emails a target a specially crafted Office document (or hosts it for download) that contains a malformed structure designed to overflow a heap buffer during parsing. When the victim opens the file - and, where applicable, exits Protected View - the overflow corrupts heap memory and executes attacker-supplied code in the context of the logged-in user, enabling malware installation or data theft. … |
| Remediation | Apply the vendor updates: Patch available per vendor advisory - install the Microsoft security updates for your specific channel/build as documented at https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-55049 (Windows editions via Microsoft Update / Click-to-Run, and macOS editions via Microsoft AutoUpdate). … Detailed patch versions, workarounds, and compensating controls in full report. |
Recommended ActionAI
Within 24 hours: Inventory all Office deployments across Office 2016, 2019, 365 Apps for Enterprise, LTSC 2021/2024, and macOS equivalents; establish patch testing timeline. …
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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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