EUVD-2026-56704
GHSA-2jmj-f42h-x4j9
Severity by source
AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N
Local file-open trigger requires victim interaction (UI:R, AV:L); no system privileges needed by attacker (PR:N); impact is memory disclosure only, with no integrity or availability consequence.
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
Out-of-bounds read in Microsoft Office allows an unauthorized attacker to disclose information locally.
AnalysisAI
Out-of-bounds memory read in Microsoft Office exposes potentially sensitive process memory contents when a victim opens a specially crafted document locally. The vulnerability affects the full Office suite across Windows and macOS - spanning Office 2016 through LTSC 2024, Office 365 for Mac, and Microsoft 365 Apps for Enterprise - with High confidentiality impact per CVSS but no integrity or availability consequence. …
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Attack ChainAIDerived
Hypothetical attack flow derived from CVE metadata
Vulnerability AssessmentAI
| Exploitation | Exploitation requires that the target user actively open a specially crafted Office document on a local machine running a vulnerable version of Microsoft Office (UI:R confirmed by CVSS vector). … Additional conditions and limiting factors are described in the full assessment. |
| Risk Assessment | The CVSS 3.1 base score of 5.5 (Medium) reflects the local attack vector (AV:L) and required user interaction (UI:R), which together substantially constrain real-world exploitability relative to the High confidentiality impact rating. … Full risk analysis with EPSS, KEV, and SSVC signal comparison available after sign-in. |
| Exploit Scenario | An attacker crafts a malicious Office document specifically designed to trigger the out-of-bounds read in the file parser and delivers it to a target via email attachment or file share. When the victim opens the document on a local machine running a vulnerable Office version, the parser reads beyond its allocated buffer boundary, potentially leaking adjacent memory contents - including pointers, heap metadata, or data from co-located memory regions - which the attacker could retrieve via a secondary channel embedded in the document. … |
| Remediation | The primary remediation is to apply Microsoft's released security update via the MSRC update guide at https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-64899 or through the Office update channel at https://aka.ms/OfficeSecurityReleases. … Detailed patch versions, workarounds, and compensating controls in full report. |
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Same weakness CWE-125 – Out-of-bounds Read
View allSame technique Information Disclosure
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External POC / Exploit Code
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