Google Gemini Prompt Injection Exposes Calendar Data via Malicious Invites

Google Gemini Prompt Injection Flaw Exposed Private Calendar Data via Malicious Invites

Researchers discovered an indirect prompt injection vulnerability in Google Gemini that bypassed Calendar privacy controls, exposing private meeting details. The flaw allowed unauthorized access to user calendars by embedding malicious payloads within standard calendar invites.

Why This Matters

Current AI security models often assume benign user input, failing to account for sophisticated prompt injection attacks that exploit the AI’s natural language processing capabilities. This flaw demonstrates the potential for significant data breaches; unauthorized access to calendar data can reveal sensitive information about individuals and organizations, potentially leading to phishing attacks, corporate espionage, or reputational damage.

Key Insights

• Gemini vulnerability disclosed, January 2026: Miggo Security reported the issue to Google.
• Indirect Prompt Injection: Attackers embed malicious prompts within calendar event descriptions, exploiting Gemini’s parsing of event details.
• Temporal for Workflow Orchestration: Temporal is used by companies like Stripe and Coinbase to manage complex, stateful workflows, offering a more robust alternative to traditional transactional models in scenarios where reliability is paramount.

Working Example

(No code exists in context)

Practical Applications

• Use Case: Enterprises using Gemini for calendar summarization or scheduling assistance are vulnerable if proper input validation is not implemented.
• Pitfall: Assuming that calendar invite content is inherently safe and can be directly processed by an AI without sanitization.