# Critical CoSnitch Vulnerability in Microsoft Copilot Enables Silent Data Theft

> Varonis Threat Labs has disclosed CoSnitch, tracked as CVE-2026-24301, a chained vulnerability in Microsoft Copilot Personal that let an attacker silently steal a victim's emails, calendar, and drive contents through a single malicious link. Microsoft patched it on August 18, following the initial disclosure back in December 2025. Varonis says it found no evidence the flaw was exploited in the wild before the fix. Technically, the attack stitched together three separate weaknesses to trigger an undocumented parameter that executed without meaningful user action, and in the researchers' testing it could reach connected accounts including Gmail, Google Drive, and Google Calendar. In other words, one click on a crafted link, and Copilot itself became the tool that pulled the data out. This is the sharp edge of giving AI assistants broad access to our inboxes and files. The more an assistant can see and act on, the more valuable it becomes as a target, and prompt-injection-style tricks turn that reach into an attack surface. Expect this class of bug, the assistant that can be quietly steered against its owner, to define the next few years of AI security work.

_Section: [Daily AI Updates](https://www.wortins.com/daily-ai) · Source: Varonis · Published Sunday, August 23, 2026_

## Wortins' read

Varonis Threat Labs has disclosed CoSnitch, tracked as CVE-2026-24301, a chained vulnerability in Microsoft Copilot Personal that let an attacker silently steal a victim's emails, calendar, and drive contents through a single malicious link. Microsoft patched it on August 18, following the initial disclosure back in December 2025. Varonis says it found no evidence the flaw was exploited in the wild before the fix. Technically, the attack stitched together three separate weaknesses to trigger an undocumented parameter that executed without meaningful user action, and in the researchers' testing it could reach connected accounts including Gmail, Google Drive, and Google Calendar. In other words, one click on a crafted link, and Copilot itself became the tool that pulled the data out. This is the sharp edge of giving AI assistants broad access to our inboxes and files. The more an assistant can see and act on, the more valuable it becomes as a target, and prompt-injection-style tricks turn that reach into an attack surface. Expect this class of bug, the assistant that can be quietly steered against its owner, to define the next few years of AI security work.

## Source

[Read the full story at Varonis](https://www.varonis.com/blog/cosnitch)

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