EUVD-2026-56714
GHSA-9fmp-h9wg-v7hh
Severity by source
AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
File-based delivery requires local processing (AV:L) and user interaction (UI:R); no attacker privileges needed (PR:N); full code execution yields C:H/I:H/A:H.
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
Integer overflow or wraparound in Microsoft Office allows an unauthorized attacker to execute code locally.
AnalysisAI
Local code execution via heap-based buffer overflow in Microsoft Office affects multiple product lines including Office 2019, 2021, 2024 LTSC, and Microsoft 365 Apps for Enterprise. An integer overflow or wraparound during document parsing leads to an undersized heap allocation (CWE-122), enabling arbitrary code execution at the privilege level of the opening user when a victim opens a maliciously crafted Office file. …
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Attack ChainAIDerived
Hypothetical attack flow derived from CVE metadata
Vulnerability AssessmentAI
| Exploitation | User interaction is required - the victim must actively open a maliciously crafted Office document (UI:R per CVSS). … Additional conditions and limiting factors are described in the full assessment. |
| Risk Assessment | The CVSS 3.1 score of 7.8 (AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H) reflects high impact across all three pillars - confidentiality, integrity, and availability - with low attack complexity once a malicious document is crafted. … Full risk analysis with EPSS, KEV, and SSVC signal comparison available after sign-in. |
| Exploit Scenario | An attacker crafts a malicious Office document (e.g., a Word .docx or Excel .xlsx file) that triggers the integer overflow during parsing of a specially structured data field, causing an undersized heap buffer to be allocated. The attacker delivers this file via phishing email or a compromised file-sharing link; when the victim opens the document in an unpatched version of Microsoft Office, the overflow corrupts adjacent heap memory, ultimately redirecting execution flow to attacker-controlled code running at the victim's user privilege level. … |
| Remediation | Apply the vendor-released patch immediately. … Detailed patch versions, workarounds, and compensating controls in full report. |
Recommended ActionAI
Within 24 hours, identify all systems running Office 2019, 2021, 2024 LTSC, or Microsoft 365 Apps for Enterprise and issue a security advisory to users prohibiting opening files from external or untrusted sources until patching is complete; within 7 days, obtain the vendor security patch and validate it in non-production test environments for compatibility with your enterprise deployments; within 30 days, complete rollout of the patch to all production systems running affected Office versions with documented tracking of completion by system and department.
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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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