Executive Summary
Varonis chained three bugs into SearchLeak, a one-click path that could pull emails, calendar details and indexed files from Microsoft 365 Copilot Enterprise Search via a trusted microsoft.com link.
What Happened
A single click on a trusted Microsoft link could have let an attacker pull emails, calendar details, and indexed files out of Microsoft 365 Copilot Enterprise Search. Researchers at Varonis Threat Labs chained three bugs into a one-click exfiltration path they call SearchLeak. Because the link pointed to a real microsoft.com domain, traditional anti-phishing and URL filtering tools were
Affected Products
- Microsoft 365 Copilot Enterprise Search
Vulnerability / Attack Technique
One-click exfiltration through a trusted-domain link
Technical Mechanism
As reported, a link on a real Microsoft domain triggered Copilot search and sent results out, evading URL filters.
AI Security Category
LLM02:2025 Sensitive Information Disclosure
Relevant Frameworks
RealGround Analysis
Trusted domains defeat link filtering. RealGround analysis: Copilot search scope determines how much a single click can leak.
Recommended Controls
- Apply Microsoft's fixes
- Limit what Copilot search indexes
Related RealGround Service
AI Security Readiness Assessment · or start with the free AI Agent Security Scanner.
Sources
thehackernews.com: https://thehackernews.com/2026/06/one-click-microsoft-365-copilot-flaw.html
Summary and analysis written by RealGround from the source above; last updated 2026-10-18.