CVE-2026-27825
Received Received - Intake
Arbitrary File Write in MCP Atlassian Enables Remote Code Execution

Publication date: 2026-03-10

Last updated on: 2026-04-02

Assigner: GitHub, Inc.

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.
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Meta Information
Published
2026-03-10
Last Modified
2026-04-02
Generated
2026-06-16
AI Q&A
2026-03-10
EPSS Evaluated
2026-06-14
NVD
CVE-2026-27825
EUVD
EUVD-2026-10810
Affected Vendors & Products
Showing 1 associated CPE
Vendor Product Version / Range
mcp-atlassian mcp_atlassian to 0.17.0 (exc)
Helpful Resources
Exploitability
CWE
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KEV
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CWE ID Description
CWE-73 The product allows user input to control or influence paths or file names that are used in filesystem operations.
CWE-22 The product uses external input to construct a pathname that is intended to identify a file or directory that is located underneath a restricted parent directory, but the product does not properly neutralize special elements within the pathname that can cause the pathname to resolve to a location that is outside of the restricted directory.
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Executive Summary

This vulnerability exists in the MCP Atlassian server used for Atlassian products like Confluence and Jira. Before version 0.17.0, the `confluence_download_attachment` tool accepts a parameter called `download_path` that does not enforce directory boundaries. This means an attacker who can invoke this tool and supply or access a malicious Confluence attachment can write arbitrary content to any file path that the server process has permission to write to.

Because the attacker controls both where the content is written and what content is written, they can execute arbitrary code on the server. For example, by writing a valid cron job entry to `/etc/cron.d/`, the attacker can achieve code execution without needing to restart the server. This vulnerability was fixed in version 0.17.0.

Impact Analysis

This vulnerability can have severe impacts including full arbitrary code execution on the affected server. An attacker could write malicious files to any location writable by the server process, potentially leading to unauthorized control over the system.

Such control could allow the attacker to manipulate data, disrupt services, install backdoors, or pivot to other parts of the network. The vulnerability has a high CVSS score of 9.0, indicating critical impact on confidentiality, integrity, and availability.

Compliance Impact

I don't know

Detection Guidance

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Mitigation Strategies

To mitigate this vulnerability, upgrade the MCP Atlassian server to version 0.17.0 or later, as this version fixes the issue.

Additionally, restrict access to the `confluence_download_attachment` MCP tool to trusted users only, since the vulnerability requires the attacker to call this tool.

Review and limit the server process's write permissions to prevent arbitrary file writes to sensitive locations.

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