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CVE-2026-27825GHSA-XJGW-4WVW-RGM4PYSEC-2026-408

MCP Atlassian has an arbitrary file write leading to arbitrary code execution via unconstrained download_path in confluence_download_attachment

Published
Last modified
published
Not listed in CISA KEV
Fix
Fixed in 0.17.0
1 proof of concept on GitHub
  • Exploitation: poc
  • Automatable: no
  • Technical impact: total

Summary

MCP Atlassian is a Model Context Protocol (MCP) server for Atlassian products (Confluence and Jira). Prior to version 0.17.0, the `confluence_download_attachment` MCP tool accepts a `download_path` parameter that is written to without any directory boundary enforcement. An attacker who can call this tool and supply or access a Confluence attachment with malicious content can write arbitrary content to any path the server process has write access to. Because the attacker controls both the write destination and the written content (via an uploaded Confluence attachment), this constitutes for arbitrary code execution (for example, writing a valid cron entry to `/etc/cron.d/` achieves code execution within one scheduler cycle with no server restart required). Version 0.17.0 fixes the issue.

Timeline

  1. CVE published
  2. CISA SSVC assessment

    Exploitation: poc · Automatable: no · Technical impact: total

  3. Record last updated
  4. EPSS reached 10%

    FIRST estimates at least a 10% chance of exploitation in the next 30 days

Affected versions

  • sooperset mcp-atlassian

    fixed in 0.17.0

  • mcp-atlassianPyPI

    fixed in 0.17.0

References 3

GitHub · sooperset/mcp-atlassian

GitHub · plutosecurity/MCPwnfluence