EUVD-2026-44167
GHSA-8v2q-jv8c-rv2h
Severity by source
AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
Local file must be opened by the user (AV:L, UI:R) with no attacker auth (PR:N); type confusion yields full code execution as the user, so C/I/A all High and 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
Access of resource using incompatible type ('type confusion') in Microsoft Office allows an unauthorized attacker to execute code locally.
AnalysisAI
Local arbitrary code execution in Microsoft Office (2016, 2019, LTSC 2021/2024, Microsoft 365 Apps for Enterprise, and Office for Mac 2021/2024) arises from a type-confusion flaw (CWE-843) that lets an attacker run code in the context of the current user when a victim opens a crafted file. The CVSS 3.1 base score is 7.8 (AV:L/AC:L/PR:N/UI:R) reflecting local vector with required user interaction and high impact to confidentiality, integrity, and availability. …
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Attack ChainAIDerived
Hypothetical attack flow derived from CVE metadata
Vulnerability AssessmentAI
| Exploitation | Exploitation requires a local victim to open or preview an attacker-crafted Office document (UI:R - user interaction is mandatory), so this cannot be triggered remotely without user action and is not automatable. … Additional conditions and limiting factors are described in the full assessment. |
| Risk Assessment | The CVSS vector (AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H, 7.8 High) describes a low-complexity, unauthenticated-but-user-interaction-dependent local attack with high impact across C/I/A - a classic 'open a malicious document' client-side bug. … Full risk analysis with EPSS, KEV, and SSVC signal comparison available after sign-in. |
| Exploit Scenario | An attacker crafts an Office document that triggers the type-confusion condition and delivers it via phishing email, a shared drive, or a download link; when the targeted user opens the file (and dismisses or bypasses Protected View), the malformed object is dereferenced as the wrong type and the attacker's payload executes with that user's privileges. No public exploit is identified at time of analysis, so this reflects the plausible path given the CVSS local vector with required user interaction rather than an observed campaign. |
| Remediation | Patch available per vendor advisory: apply the Microsoft security update for CVE-2026-55022 documented in the MSRC Update Guide at https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-55022, which covers Windows Office (365 Apps for Enterprise, 2016, 2019, LTSC 2021, LTSC 2024) and the macOS builds (Office 365/LTSC for Mac 2021 and 2024); the exact fixed build numbers are listed on that page and should be pushed via Microsoft Update, Click-to-Run, or your patch-management system. … Detailed patch versions, workarounds, and compensating controls in full report. |
Recommended ActionAI
Within 24 hours: identify all affected Microsoft Office installations (2016, 2019, LTSC 2021/2024, Microsoft 365 Apps for Enterprise, Office for Mac 2021/2024) through asset management tools and Configuration Manager/Intune reporting. …
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Local code execution in Microsoft Office (2016, 2019, LTSC 2021/2024, Microsoft 365 Apps, and the macOS editions) arises
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Local code execution in Microsoft Office (including Microsoft 365 Apps for Enterprise, Office 2016/2019, and Office LTSC
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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 technique Memory Corruption
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External POC / Exploit Code
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