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National Vulnerability Database

National Vulnerability Database

NVD

National Vulnerability Database
  1. Vulnerabilities

CVE-2025-34072 Detail

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.


Metrics

 
NVD enrichment efforts reference publicly available information to associate vector strings. CVSS information contributed by other sources is also displayed.
CVSS 4.0 Severity and Vector Strings:

NIST CVSS score
NIST: NVD
N/A
NVD assessment not yet provided.

Nist CVSS score does not match with CNA score
CNA:  VulnCheck
CVSS-B 9.3 CRITICAL
Vector:  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

References to Advisories, Solutions, and Tools

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URL Source(s) Tag(s)
https://embracethered.com/blog/posts/2025/security-advisory-anthropic-slack-mcp-server-data-leakage/ VulnCheck
https://vulncheck.com/advisories/anthropic-slack-mcp-server-data-exfiltration VulnCheck

Weakness Enumeration

CWE-ID CWE Name Source
CWE-200 Exposure of Sensitive Information to an Unauthorized Actor VulnCheck  
CWE-20 Improper Input Validation VulnCheck  

Change History

1 change records found show changes

Quick Info

CVE Dictionary Entry:
CVE-2025-34072
NVD Published Date:
07/02/2025
NVD Last Modified:
07/03/2025
Source:
VulnCheck