Threats affecting pkg:brew/mcp-atlassian

A command injection vulnerability exists in FastMCP when installing the claude-code or gemini-cli tools on Windows. Server names containing shell metacharacters such as '&' can cause arbitrary command execution due to how Windows .cmd wrappers are invoked via cmd.exe. This affects FastMCP versions from 0.11.9 up to but not including 0.23.0. The issue does not affect macOS or Linux, nor config-file-based install targets. The vulnerability is patched in version 0.23.0 by validating server names to reject shell metacharacters.

A command injection vulnerability exists in the FastMCP Cursor installer component of mcp-atlassian versions 0.11.9 and 0.11.10. The vulnerability allows an attacker who can control the server_name parameter to execute arbitrary OS commands on Windows hosts running the affected software. This occurs because server_name is embedded without sanitization into a shell command executed with cmd.exe /c start, enabling command injection via Windows command metacharacters. The issue is fixed in version 0.11.11.

A reflected Cross-Site Scripting (XSS) vulnerability exists in the FastMCP OAuth client's callback page. User-controlled input parameters, such as 'error', are embedded into the callback page without proper escaping or sanitization, allowing arbitrary JavaScript execution in the callback server's origin. This affects FastMCP versions from 0.11.9 up to but not including 0.11.11. The vulnerability has a CVSS 4.0 base score of 5.3 (medium severity).