Come To Think of It...

There is a new vulnerability in Microsoft 365 Copilot Enterprise called SearchLeak, and on its own it is the kind of finding that generates a CVE, a Microsoft blog post, and a few security team ticket updates. But the architecture of the attack tells a bigger story about what happens when prompt injection meets the old bug classes that security teams have been wrestling with for decades. SearchLeak chains three separate weaknesses into a silent data exfiltration pipeline. The first is a parameter-to-prompt injection: the search q parameter in Copilot Enterprise Search passes user input directly into the AI engine, treating it as both a search query and executable instructions. Unlike the regular Copilot chat feature, Enterprise Search is designed to pull from company data — emails, SharePoint files, OneDrive documents — so an injected prompt can surface anything the victim user has access to. The second weakness is an HTML rendering race condition: during Copilot's streaming res...