---
title: "DEF CON Copirate 365 Talk: Plundering in the Depths of Microsoft Copilot (CVE-2026-24299) · Embrace The Red"
url: https://daily.dev/posts/def-con-copirate-365-talk-plundering-in-the-depths-of-microsoft-copilot-cve-2026-24299-embrace--mtlczhfal
source_url: https://embracethered.com/blog/posts/2026/defcon-talk-copirate-365
type: article
source: "Embrace The Red"
published: 2026-05-04T13:08:28.733Z
updated: 2026-05-04T13:08:55.904Z
tags: ["llm", "ai-security", "prompt-injection", "data-exfiltration", "microsoft-copilot"]
reading_time: 18
upvotes: 0
comments: 0
language: en
---

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# DEF CON Copirate 365 Talk: Plundering in the Depths of Microsoft Copilot (CVE-2026-24299) · Embrace The Red

**[Embrace The Red](https://daily.dev/sources/embracethered)** · 18 min read · 0 upvotes · 0 comments

## Summary

A detailed writeup of a DEF CON Singapore talk covering a chain of vulnerabilities in Microsoft 365 Copilot and Consumer Copilot (CVE-2026-24299). The research demonstrates: (1) HTML preview as a data exfiltration channel via CSS font-face bypass, (2) Delayed Tool Invocation to plant instructions for later execution, (3) hijacking M365 Copilot's long-term memory via indirect prompt injection to write false or malicious memories, and (4) combining persistence with data exfiltration into a 'SpAIware' backdoor. The attack chain allows an attacker to silently exfiltrate emails, passwords, and other sensitive data from any future Copilot conversation after a one-time compromise. All issues were patched by Microsoft in early 2026. Key takeaways include the dangers of auto-committing memories without audit logs, the unreliability of CSP as a security boundary across Copilot hosting environments, and the need for explicit security contracts for AI widgets.

## Full article

daily.dev links to this article rather than hosting it. Read it at the original source: <https://embracethered.com/blog/posts/2026/defcon-talk-copirate-365>

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Tags: [#llm](https://daily.dev/tags/llm), [#ai-security](https://daily.dev/tags/ai-security), [#prompt-injection](https://daily.dev/tags/prompt-injection), [#data-exfiltration](https://daily.dev/tags/data-exfiltration), [#microsoft-copilot](https://daily.dev/tags/microsoft-copilot)

[View this post on daily.dev](https://daily.dev/posts/def-con-copirate-365-talk-plundering-in-the-depths-of-microsoft-copilot-cve-2026-24299-embrace--mtlczhfal)