CVE-2025-34072

Summary

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 Software

VendorProductVersion RangeStatus
AnthropicSlack MCP Server0affected

Weaknesses

  • CWE-200: CWE-200 Exposure of Sensitive Information to an Unauthorized Actor
  • CWE-20: CWE-20 Improper Input Validation

ADP Enrichment

CISA ADP Vulnrichment

  • SSVC:
  • Exploitation: poc
    • Automatable: no
    • Technical Impact: partial

References