CVE-2025-34072 — Anthropic Slack MCP Server Data Exfiltration via Link Unfurling
A data exfiltration vulnerability exists in Anthropic’s deprecated Slack Model Context Protocol (MCP) Server via automatic link unfurling. When an AI agent using the Slack MCP S…
Published: 2025-07-02 · CVSS: 9.3 · CVSS 4.0
A data exfiltration vulnerability exists in Anthropic’s deprecated Slack Model Context Protocol (MCP) Server via automatic link unfurling. When an AI agent using the Slack MCP Server processes untrusted data, it can be manipulated to generate messages containing attacker-crafted hyperlinks embedding sensitive data. Slack’s link preview bots (e.g., Slack-LinkExpanding, Slackbot, Slack-ImgProxy) will then issue outbound requests to the attacker-controlled URL, resulting in zero-click exfiltration of private data.
Source: CVE Program · Revision 8b16575c39f1e1810c5e863010da073d2d3285e7