Critical 0-Click Microsoft Excel Security Bug Lets Copilot Steal Data

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This article is one source in a clustered incident — the cluster page carries the summary, timeline and every other outlet covering it.

Multiple Vulnerabilities in Microsoft Office Excel (CVE-2026) Microsoft Office Excel has multiple vulnerabilities that allow unauthorized attackers to execute code locally. These include an out-of-bounds read, use after free, untrusted pointer dereference, heap-based buffer overflow, and type confusion. A cross-site scripting vulnerability also allows information disclosure over a network. 14 sources 72