How safe is Copilot for IT & software development?

Copilot Cowork relies on Anthropic's Claude models for demanding tasks. Because that processing takes place outside the EU Data Boundary, Anthropic is switched off by default in European Microsoft 365 tenants. Anyone who turns it on has data processed outside the EU Data Boundary; at the same time, pay-per-use (Copilot Credits) is coming, in the Netherlands postponed until 1 December 2026. source

Research lab Air Security publicly disclosed Plugin4Shell on 18 September 2026: a zero-click RCE in the plugin mechanism of AI coding agents. The agent pins a plugin to a commit hash but does not verify that the retrieved code belongs to that hash; whoever controls or takes over the upstream repository can thus have code executed during the automatic background update, without any action by the user. GitHub Copilot had no patch at the time of publication, although the report was made to all vendors in June 2026. GDPR relevance: plugins run with the developer's rights (source code, cloud credentials, SSH keys, internal repositories, production systems). If you process personal data on or via development machines, this directly affects your security measures under Art. 32 GDPR. Measures: inventory installed plugins and the owners of those repositories, disable automatic plugin updates where possible, and restrict credentials on development machines. Note: this concerns the GitHub Copilot coding agent, not Microsoft 365 Copilot. source

The Claude models within Microsoft 365 Copilot fall outside the EU Data Boundary; 'flex routing' can route outside the EU during peak load and can be switched off by administrators. source