What happened
CVE-2026-41106 (CVSS 9.3 Critical) is an open-redirect vulnerability in Microsoft 365 Copilot that allowed privilege escalation. It was published July 2, 2026 and covered prominently in the July 4, 2026 Threat-Modeling.com Vulnerability Intelligence Report alongside a companion Exchange Online flaw (CVE-2026-54998); Microsoft patched it cloud-side.
Why it matters
M365 Copilot is one of the most widely deployed enterprise GenAI assistants; a critical privilege-escalation flaw in its trust/redirect handling — even though already remediated — illustrates how open-redirect-class bugs in AI copilots can be chained into account or tenant-level privilege escalation across massive enterprise user bases.
Attack vector
An open redirect ('URL Redirection to Untrusted Site', CWE-601) in M365 Copilot allows an unauthorized attacker to elevate privileges over a network, requiring user interaction (e.g., clicking a crafted link that bounces through Copilot's trusted redirect flow to an attacker-controlled destination, then leveraging that trust to escalate privileges).
Affected systems
Microsoft 365 Copilot (cloud-hosted, exclusively-hosted-service)
Mitigation
Patched server-side by Microsoft; no customer action required (published/fixed 2026-07-02, per Microsoft advisory GHSA-6xf4-794h-3f7w).