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CVE PROGRAM SOURCE RECORD9.3 Critical

CVE-2025-34072

Anthropic Slack MCP Server Data Exfiltration via Link Unfurling

Read JSON ↗CVE.org ↗
Status
Published
Published
Updated
Assigning organization
VulnCheck

Description

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.

Affected products

Version statuses are supplied by the assigning organization. Consult the original record for detailed ranges and platform conditions.

Anthropic Slack MCP Server

Default version status: unaffected

  • 0affected

References