CVE-2026-27825
CRITICAL
GHSA-xjgw-4wvw-rgm4
CVSS Vector
CVSS:3.1/AV:A/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
Lifecycle Timeline
3Tags
Description
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.
Analysis
MCP Atlassian server has a path traversal vulnerability enabling unauthorized access to Confluence and Jira data outside the intended scope.
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Remediation
Within 24 hours: Inventory all systems running MCP Atlassian and confirm versions prior to 0.17.0; disable the confluence_download_attachment tool if possible or restrict network access to the MCP server. Within 7 days: Implement network segmentation to limit MCP server communications; deploy WAF rules to block suspicious download_path parameters; conduct audit of recent file writes to detect exploitation. …
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External POC / Exploit Code
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