EUVD-2026-35543
GHSA-wqhv-6ff2-ww7r
Severity by source
AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Primary rating from Vendor (microsoft).
CVSS VectorVendor: microsoft
CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Lifecycle Timeline
3DescriptionCVE.org
Heap-based buffer overflow in Microsoft Office allows an unauthorized attacker to execute code locally.
AnalysisAI
Local code execution in Microsoft Office is possible via a heap-based buffer overflow that an unauthorized attacker can trigger without user interaction, yielding full confidentiality, integrity, and availability impact on the host. The flaw is rated 8.4 (CVSS:3.1) and was disclosed by Microsoft's Security Response Center, but no public exploit has been identified at the time of analysis. Despite the CWE-121 tagging as a stack overflow, the description and CWE-122 class indicate the corruption occurs on the heap, so defenders should treat this as a memory-corruption RCE-class issue requiring prompt patching.
Technical ContextAI
Microsoft Office is the affected product family, encompassing desktop productivity applications that parse complex document formats (DOC/DOCX, XLS/XLSX, PPT/PPTX, RTF, OLE streams) through shared parsing libraries. The root cause is CWE-121 (Stack-based Buffer Overflow) per the input, though the description specifically calls out a heap-based buffer overflow - a memory-safety class where a write past the bounds of a heap-allocated buffer corrupts adjacent metadata or function pointers. Such flaws in Office typically arise in file-format parsers handling malformed records, and successful exploitation can pivot the corruption into arbitrary code execution in the context of the Office process.
RemediationAI
No vendor-released patch version was supplied in the input data; consult the Microsoft Security Update Guide at https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-45463 for the exact KB articles and build numbers, then deploy the corresponding security updates through Microsoft Update, WSUS, Intune, or your standard patch-management channel. Until patches are applied, compensating controls include disabling the Outlook/Explorer preview pane and thumbnail handlers for Office formats to block automatic parsing of untrusted attachments (trade-off: reduced usability for triaging mail), enforcing Protected View for files from the internet and email attachments via Group Policy (trade-off: users must explicitly enable editing), blocking inbound Office documents at the mail gateway from untrusted senders or converting them to PDF, and applying Attack Surface Reduction rules (e.g., 'Block Office applications from creating child processes') via Microsoft Defender to limit post-exploitation pivot.
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Same weakness CWE-121 – Stack-based Buffer Overflow
View allSame technique Stack Overflow
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External POC / Exploit Code
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