Critical Microsoft Excel bug weaponizes Copilot Agent for zero-click information disclosure attack


After a whopper of a Patch Tuesday last month, with six Microsoft flaws exploited as zero-days, March didn’t exactly roar in like a lion. Just two of the 83 Microsoft CVEs released on Tuesday are listed as publicly known, and none is under active exploitation, which we’re sure is a welcome change to sysadmins.

Another eight of the 83 Microsoft CVEs are considered critical, and one of these – to quote Zero Day Initiative chief bug hunter Dustin Childs – is “fascinating.” Plus, it’s got an AI-attack component, so we’re going to start with it. CVE-2026-26144 is a critical-severity information disclosure vulnerability in Microsoft Excel.

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Source: The Register News


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