Security Advisory: Anthropic's Slack MCP Server Vulnerable to Data Exfiltration
Brief
This is a security advisory for a data leakage and exfiltration vulnerability in a popular, but now deprecated and unmaintained, Slack MCP Server from Anthropic.
If you are using this MCP server, or run an “MCP Store” that hosts it, it is advised that you analyze how this threat applies to your use case and apply a patch as needed.
Anthropic’s Slack MCP Server
When Anthropic introduced MCP they published reference server implementations on Github .