CVE-2026-27825
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
Description
CVSS Scores
EPSS Scores
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Meta Information
Affected Vendors & Products
| Vendor | Product | Version / Range |
|---|---|---|
| mcp-atlassian | mcp_atlassian | to 0.17.0 (exc) |
Helpful Resources
Exploitability
| CWE ID | Description |
|---|---|
| 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. |
| CWE-73 | The product allows user input to control or influence paths or file names that are used in filesystem operations. |
Attack-Flow Graph
AI Powered Q&A
Can you explain this vulnerability to me?
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.
How can this vulnerability impact me? :
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.
How does this vulnerability affect compliance with common standards and regulations (like GDPR, HIPAA)?:
I don't know
How can this vulnerability be detected on my network or system? Can you suggest some commands?
I don't know
What immediate steps should I take to mitigate this vulnerability?
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.