EUVD-2026-44192
GHSA-jgr3-cvvq-qqh3
Severity by source
AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
Local file-parsing flaw requiring the user to open a malicious document (AV:L, UI:R), no prior privileges (PR:N), yielding full code execution as the user (C/I/A:H).
Primary rating from Vendor (microsoft).
CVSS VectorVendor: microsoft
Lifecycle Timeline
2DescriptionCVE.org
Heap-based buffer overflow in Microsoft Office allows an unauthorized attacker to execute code locally.
AnalysisAI
Local code execution in Microsoft Office (2016, 2019, LTSC 2021/2024, Microsoft 365 Apps for Enterprise, and Office for Mac) arises from a heap-based buffer overflow (CWE-122) triggered when a user opens a maliciously crafted document. Rated CVSS 7.8 (AV:L/UI:R), an attacker who convinces a victim to open a weaponized file can run arbitrary code in the context of the current user. Microsoft has released a patch; there is no public exploit identified at time of analysis and it is not listed in CISA KEV.
Technical ContextAI
The flaw is a CWE-122 heap-based buffer overflow within Microsoft Office's document/file parsing code. Office applications parse complex binary and OOXML file formats, and improper bounds validation when copying attacker-controlled data into a heap allocation lets an oversized write corrupt adjacent heap structures, which can be groomed to hijack control flow. The CPE data confirms the affected surface spans multiple Office channels - Microsoft 365 Apps for Enterprise, Office 2016, Office 2019, Office LTSC 2021 and 2024, and the macOS equivalents (Office 365 for Mac, Office LTSC for Mac 2021/2024) - indicating the vulnerable component is in shared cross-platform parsing logic rather than a single edition-specific feature.
RemediationAI
Patch available per vendor advisory - apply the Microsoft security update for CVE-2026-55129 via the MSRC Update Guide at https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-55129, ensuring Windows Office channels (Microsoft 365 Apps, Office 2016/2019, LTSC 2021/2024) and macOS builds each receive their respective fixed builds through Microsoft Update, Click-to-Run, or AutoUpdate for Mac. Exact fixed build numbers are not provided in the input and should be taken from the advisory. Until deployment completes, reduce exposure by enabling Protected View and blocking macros/active content for files originating from the internet (Mark-of-the-Web), and by restricting or sandboxing documents from untrusted email and web sources; note that aggressive Protected View or attachment-blocking policies can disrupt legitimate document workflows and should be scoped to external content.
Local code execution in Microsoft Word (and Office/SharePoint components that render Word content) stems from an integer
Arbitrary code execution in Microsoft Office Word (and the broader Office/365/SharePoint family) arises from a stack-bas
Local code execution in Microsoft Word (part of Microsoft 365 Apps, Office 2019, Office LTSC 2021/2024, and Office for M
Arbitrary code execution in Microsoft PowerPoint (and the broader Microsoft Office/365 suite on Windows and macOS) arise
Local code execution in Microsoft Office PowerPoint (including Microsoft 365 Apps, Office 2019, Office LTSC 2021/2024, a
Local code execution in Microsoft Office PowerPoint (CWE-122 heap-based buffer overflow) lets an unauthorized attacker r
Local code execution in Microsoft Word (and the wider Microsoft Office / Microsoft 365 Apps family) lets an unauthorized
Local code execution in Microsoft Word (Office 2016/2019, Microsoft 365 Apps, Office LTSC 2021/2024) arises from a heap-
Local code execution in Microsoft Office Word (CWE-416 use-after-free) allows an unauthorized attacker to run arbitrary
Local code execution in Microsoft Office Word (Microsoft 365 Apps, Office 2019/LTSC 2021/2024, Word 2016, and the macOS
Local code execution in Microsoft Office Word (via a stack-based buffer overflow, CWE-121) lets an attacker run arbitrar
Local code execution in Microsoft Office Word (across Microsoft 365 Apps, Office 2019/LTSC 2021/2024, Office for Mac, an
Same weakness CWE-122 – Heap-based Buffer Overflow
View allSame technique Buffer Overflow
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External POC / Exploit Code
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