CVE-2025-34072 (GCVE-0-2025-34072)

Vulnerability from cvelistv5 – Published: 2025-07-02 13:46 – Updated: 2025-07-02 20:29
VLAI?
Title
Anthropic Slack MCP Server Data Exfiltration via Link Unfurling
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.
Severity ?
9.3 (Critical)
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:N/VA:N/SC:H/SI:H/SA:H
CWE
  • CWE-200 - Exposure of Sensitive Information to an Unauthorized Actor
  • CWE-20 - Improper Input Validation
Assigner
References
https://embracethered.com/blog/posts/2025/securit… third-party-advisorytechnical-descriptionexploit
https://vulncheck.com/advisories/anthropic-slack-… third-party-advisory
Impacted products
Vendor Product Version
Anthropic Slack MCP Server Affected: 0
Create a notification for this product.
Credits
wunderwuzzi of Embrace The Red
Show details on NVD website
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  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
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  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.



Detection rules are retrieved from Rulezet.