EUVD-2026-56574
GHSA-5fx6-3jpg-j6pm
Severity by source
AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N
Local file-based trigger requires user to open crafted content (AV:L, UI:R); no prior authentication needed (PR:N); only confidentiality impacted (C:H/I:N/A:N), consistent with described information disclosure.
Primary rating from Vendor (microsoft).
CVSS VectorVendor: microsoft
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N
Lifecycle Timeline
3DescriptionCVE.org
Improper input validation in Microsoft Office Excel allows an unauthorized attacker to disclose information locally.
AnalysisAI
Improper input validation in Microsoft Office Excel enables a local attacker to disclose sensitive information when a target user opens a specially crafted file. The vulnerability affects a broad swath of Microsoft Office product lines - including Microsoft 365 Apps for Enterprise, Office LTSC 2021 and 2024, Office 2019, Office 365 for Mac, and Word 2016 - across both Windows and macOS platforms. …
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Attack ChainAIDerived
Hypothetical attack flow derived from CVE metadata
Vulnerability AssessmentAI
| Exploitation | Exploitation requires the target user to actively open a specially crafted Excel file on their local system - user interaction (UI:R) is mandatory, and the attack has no remote unauthenticated network path. … Additional conditions and limiting factors are described in the full assessment. |
| Risk Assessment | The CVSS 3.1 base score of 5.5 (AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N) reflects a medium-severity finding: the high confidentiality impact is substantially tempered by the mandatory local attack vector and required user interaction. … Full risk analysis with EPSS, KEV, and SSVC signal comparison available after sign-in. |
| Exploit Scenario | An attacker crafts a malicious Excel workbook that triggers the improper input validation flaw and delivers it to a target user via email attachment, shared drive, or download link. The target user opens the file in an unpatched version of Microsoft Office Excel, causing the application to process attacker-controlled input without proper validation and leaking sensitive local data - such as portions of memory or accessible file contents - back to a location the attacker can retrieve. … |
| Remediation | Apply vendor-released patches through standard Microsoft Update channels. … Detailed patch versions, workarounds, and compensating controls in full report. |
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Same weakness CWE-20 – Improper Input Validation
View allSame technique Information Disclosure
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External POC / Exploit Code
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