EUVD-2026-56424
GHSA-7vp4-c5c5-q52v
Severity by source
AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
AV:L and PR:N reflect file-based delivery requiring no attacker privileges; UI:R captures the mandatory victim-opens-file gating condition; C/I/A:H reflects full session compromise upon successful exploitation.
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
3DescriptionCVE.org
Heap-based buffer overflow in Microsoft Office allows an unauthorized attacker to execute code locally.
AnalysisAI
Local code execution in Microsoft Office is possible when a user opens a specially crafted document that triggers a heap-based buffer overflow (CWE-122), granting the attacker full control over the victim's user session. The vulnerability spans the entire modern Office portfolio - Microsoft 365 Apps for Enterprise, Office 2019, LTSC 2021, LTSC 2024, and macOS equivalents - making the attack surface exceptionally broad. …
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Attack ChainAIDerived
Hypothetical attack flow derived from CVE metadata
Vulnerability AssessmentAI
| Exploitation | The victim must actively open a specially crafted Office document on an affected installation of Microsoft Office - this is the sole gating condition reflected in the UI:R metric. … Additional conditions and limiting factors are described in the full assessment. |
| Risk Assessment | The CVSS 7.8 score (AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H) reflects a high-severity but user-interaction-dependent vulnerability: exploitation requires the victim to open a malicious file, which is the single gating condition. … Full risk analysis with EPSS, KEV, and SSVC signal comparison available after sign-in. |
| Exploit Scenario | An attacker crafts a malicious Office document - such as a Word .docx or Excel .xlsx file - engineered to trigger a heap-based buffer overflow in Office's document parser when opened. The attacker delivers the file to a target via a phishing email or compromised file-sharing service; when the victim opens the document, the overflow corrupts heap memory and redirects execution to attacker-controlled shellcode, running with the victim's user-level privileges. … |
| Remediation | Apply vendor-released patches immediately via Microsoft's standard Office update mechanism. … Detailed patch versions, workarounds, and compensating controls in full report. |
Recommended ActionAI
Within 24 hours, inventory all affected Microsoft Office installations across the organization and establish a prioritized deployment plan for systems in sensitive roles. …
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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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