EUVD-2026-56699
GHSA-625x-f6gf-q9j2
Severity by source
AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
Local vector with UI:R matches malicious document attack pattern; PR:N because any user account can open a file, no elevated privileges needed.
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
Heap-based buffer overflow in Microsoft Office allows local code execution across a wide range of Office versions on both Windows and macOS when a victim opens a specially crafted document. The CVSS vector (AV:L/AC:L/PR:N/UI:R) confirms that no privileges are required - only that a user interacts with malicious content - making this practically reachable via phishing or drive-by document delivery despite the local attack vector. …
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Attack ChainAIDerived
Hypothetical attack flow derived from CVE metadata
Vulnerability AssessmentAI
| Exploitation | The CVSS vector (AV:L/AC:L/PR:N/UI:R) specifies that exploitation requires: (1) the victim must actively open or interact with a malicious Office document - passive delivery is insufficient; (2) no privileges are required on the attacker's side; and (3) the victim's system must be running an unpatched version of one of the affected Microsoft Office products (Office 2016 through 365/LTSC current on Windows or macOS). … Additional conditions and limiting factors are described in the full assessment. |
| Risk Assessment | The CVSS base score of 7.8 (High) reflects high confidentiality, integrity, and availability impact with low attack complexity, no privileges required, and user interaction required. … Full risk analysis with EPSS, KEV, and SSVC signal comparison available after sign-in. |
| Exploit Scenario | An attacker sends a phishing email to a target employee containing a maliciously crafted Office document (e.g., a Word .docx or Excel .xlsx file) that triggers the heap-based buffer overflow in Microsoft Office's parser when opened. The victim opens the file in an unpatched Office installation, the overflow corrupts heap memory in a controlled manner, and the attacker achieves arbitrary code execution in the context of the victim's user account. … |
| Remediation | Apply the vendor-released patch immediately. … Detailed patch versions, workarounds, and compensating controls in full report. |
Recommended ActionAI
Within 24 hours, issue a user security advisory emphasizing caution with unexpected Office documents and disabling macros where feasible. …
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Threat intelligence, references, and detailed analysis are available after sign-in.
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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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