EUVD-2026-56572
GHSA-2m8h-7r9c-g9xm
Severity by source
AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N
Requires local file open (AV:L), no attacker privileges (PR:N), user must open crafted document (UI:R), impact is confidentiality-only via memory disclosure.
Primary rating from NVD.
CVSS VectorNVD
Lifecycle Timeline
3DescriptionNVD
Out-of-bounds read in Microsoft Office allows an unauthorized attacker to disclose information locally.
AnalysisAI
Out-of-bounds read in Microsoft Office (Windows and macOS editions, including LTSC 2024, LTSC 2021, 2019, and 365 Apps) enables local information disclosure when a user opens a maliciously crafted document. The CVSS vector (AV:L/UI:R) confirms exploitation is constrained to local, user-triggered scenarios with no code execution or data modification capability. Microsoft has released patches across all affected product lines; no public exploit code or CISA KEV listing exists at time of analysis.
Technical ContextAI
The vulnerability is rooted in CWE-125 (Out-of-Bounds Read), a memory-safety defect in Microsoft Office's document-parsing subsystem. When Office processes a specially crafted file, the parser reads beyond the bounds of an allocated buffer, potentially exposing adjacent in-memory contents - which could include sensitive data such as credentials, cryptographic keys, or other document content loaded in memory. The CVSS vector (AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N) indicates the flaw manifests at the local application layer requiring user interaction, not a remotely reachable network service. Affected products span both Windows builds (Office LTSC 2024, LTSC 2021, 2019, Microsoft 365 Apps for Enterprise) and macOS builds (Office 365 for Mac, LTSC for Mac 2021, LTSC for Mac 2024), as enumerated under EUVD-2026-56572. The tag 'Buffer Overflow' in the source data refers to the memory-boundary violation class rather than a separate overflow condition; the operative CWE is CWE-125.
RemediationAI
Microsoft has released patches for all affected product lines. Windows users running Office LTSC 2024, LTSC 2021, 2019, or Microsoft 365 Apps for Enterprise should apply the latest cumulative update available via Microsoft Update or the Microsoft Security Response Center at https://aka.ms/OfficeSecurityReleases. macOS users of Office 365 for Mac, Office LTSC for Mac 2021, and Office LTSC for Mac 2024 should update to build 16.112.26081010 or later via Microsoft AutoUpdate or the Mac App Store. As a compensating control prior to patching, organizations should enforce Office Protected View policies to sandbox externally sourced documents and suppress automatic rendering of untrusted files - note that Protected View reduces but does not eliminate risk if users override the prompt. User awareness training to avoid opening unsolicited Office attachments provides additional defense given the UI:R exploitation requirement.
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Same weakness CWE-125 – Out-of-bounds Read
View allSame technique Buffer Overflow
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External POC / Exploit Code
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