Microsoft 365 Copilot

Varonis Threat Labs disclosed CVE-2026-42824, a critical flaw in Microsoft 365 Copilot Enterprise Search. Clicking a single crafted link chained three bugs: injection of the URL parameter into the prompt, a rendering race condition, and abuse of Content Security Policy allowlisting to exfiltrate data through Bing's infrastructure. The attack could reach emails and calendar details, indexed SharePoint and OneDrive files, one-time and MFA codes, password-reset links, meeting notes and salary data. Because Copilot Enterprise is a managed service, tenant admins could not patch it themselves; Microsoft mitigated the flaw on its backend.

Disclosed in June 2025, EchoLeak (CVE-2025-32711, CVSS 9.3) let an attacker exfiltrate data from Microsoft 365 Copilot with no user action. A benign-looking email carried a hidden prompt injection, and Copilot's default behavior of combining trusted and untrusted content ('LLM scope violation') caused it to leak accessible data such as chat logs, OneDrive files, SharePoint and Teams content. Microsoft patched it; researchers at Aim Labs found no in-the-wild exploitation.