Claude Cowork File Exfiltration
Date: 2026-01
Affected: Claude Cowork File Exfiltration
Attack vector: prompt-injection
Category: real-world
Severity: High

Claude Cowork could be tricked via indirect prompt injection into uploading user files to an attacker's Anthropic account using curl to the whitelisted Anthropic Files API. Reused the same exfiltration vector previously reported for Claude Code. Anthropic shipped Cowork with this known vulnerability.


Mitigations:

Architectural layers (MAESTRO):