EUVD-2026-44155
GHSA-r8f5-8f3p-vxp4
Severity by source
AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
Client-side document parsing bug: attacker needs no auth (PR:N) but victim must open the file (UI:R, AV:L), and successful memory corruption yields full C/I/A compromise as the user.
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 (Microsoft 365 Apps for Enterprise, Office 2016/2019, and Office LTSC 2021/2024) arises from a heap-based buffer overflow (CWE-122) that an attacker triggers by convincing a user to open a maliciously crafted Office document. Successful exploitation yields full code execution in the context of the current user, with high impact to confidentiality, integrity, and availability. There is no public exploit identified at time of analysis and it is not listed in CISA KEV; SSVC rates current exploitation as none.
Technical ContextAI
The flaw is a CWE-122 heap-based buffer overflow within Microsoft Office's document parsing/rendering code. Heap overflows occur when a function writes more data into a heap-allocated buffer than it was sized for, corrupting adjacent heap metadata or object pointers; in file-format parsers this typically stems from trusting an attacker-controlled length or count field in the document structure. The affected CPEs identify the Office application family (microsoft_365_apps_for_enterprise, microsoft_office_2016, microsoft_office_2019, microsoft_office_ltsc_2021, microsoft_office_ltsc_2024), meaning the vulnerable component is shared Office code rather than a single standalone application. Because Office documents are a routine email and web delivery vector, a parser-level memory-corruption bug of this class is a classic path to client-side code execution.
RemediationAI
Patch available per vendor advisory: apply the Microsoft security update for CVE-2026-50301 from the MSRC update guide at https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-50301, which lists the fixed build for each affected channel (Microsoft 365 Apps for Enterprise, Office 2016, Office 2019, Office LTSC 2021, and Office LTSC 2024); the input does not specify an exact fixed version, so pull the precise build from that advisory. For Microsoft 365 Apps, ensure the click-to-run update channel is current; for Office 2016/2019/LTSC, deploy the corresponding cumulative/security update via WSUS, Microsoft Update, or Intune. As interim compensating controls until patching completes, enforce Protected View and 'Block macros/active content from the Internet' so files from email and web open in a sandboxed read-only state, use Mark-of-the-Web-aware handling to keep downloaded documents in Protected View, and restrict or block inbound Office attachments from untrusted senders at the mail gateway - the trade-off is that aggressive Protected View or attachment blocking can disrupt legitimate document workflows and requires user awareness to avoid users clicking 'Enable Editing' on hostile files.
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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