GCD AI RADAR
incidents/AIR-2026-0356

EchoLeak Zero-Click Prompt Injection on M365 Copilot

Attack on AI1 Research / proof of conceptPrompt injectionAgent hijackData leak

Researchers uncovered a zero-click prompt injection vulnerability in Microsoft 365 Copilot exploiting RAG context. Malicious emails triggered unauthorized data retrieval and subsequent exfiltration without user interaction.

Details

type
Attack on AI
An AI model, agent or AI-powered product was the thing exploited, abused or leaked.
categories
  • Prompt injectionprimary
    Untrusted content (web pages, documents, emails, tool output) steers a model into ignoring its instructions.
  • Agent hijack
    An AI agent is tricked into unauthorized actions: tool misuse, data exfiltration through the agent, or acting against its principal.
  • Data leak
    Training data, chat logs, system prompts, model weights or other AI-system data exposed.
owasp llm top 10
mitre atlas
Both rows are derived from the type and categories (OWASP 2025 edition, ATLAS release 2026.09), not classified per record. How
severity
1 · Research / proof of concept
Demonstrated by researchers; no known real-world exploitation.
targets
Microsoft
products
Microsoft 365 Copilot
incident date
May 2025 (approx.)
first reported
30 Jun 2026
origin
MITRE ATLAS
Derived from MITRE ATLAS (Apache 2.0, © MITRE).
classifier confidence
0.95 · published at or above 0.80; see the methodology
tags
echoleak · prompt-injection · m365-copilot · rag
record
created 2026-10-18 06:55Z · updated 2026-10-18 06:55Z · json

Sources · 4

  1. 2026-06-30
    EchoLeak: Zero-Click Prompt Injection Targeting M365 Copilot for Data Exfiltration
    MITRE ATLAS · atlas.mitre.org/studies/AML.CS0059
  2. 2026-06-30
    EchoLeak: The First Real-World Zero-Click Prompt Injection Exploit in a Production LLM System
    arXiv · arxiv.org/abs/2509.10540
  3. 2026-06-30
    CVE-2025-32711
    cve.org · cve.org/CVERecord?id=CVE-2025-32711
  4. 2026-06-30
    Breaking down 'EchoLeak', the First Zero-Click AI Vulnerability Enabling Data Exfiltration from Microsoft 365 Copilot
    catonetworks.com · catonetworks.com/blog/breaking-down-echoleak

Titles and links belong to their publishers. The summary above is written by GCD AI RADAR in its own words; data is CC BY-SA 4.0.

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