CVE-2026-77266: Mcp-Atlassian Mcp Atlassian

Medium severity, CVSS 6.5. EPSS: 0.4% chance of exploitation in the next 30 days.

MCP Atlassian is a Model Context Protocol (MCP) server for Atlassian products (Confluence and Jira). Prior to 0.22.0, upload_attachment accepts absolute paths and traversal sequences without constraining the resolved path to the server workspace. An MCP caller with attachment access can read a chosen server-local file and exfiltrate it through Jira or Confluence. The advisory traces the vulnerable input and processing flow through upload_attachment, file_path, and path traversal, which identify the affected entry points, controls, and code paths. This issue is fixed in version 0.22.0.

Affected products

Published 2026-09-22. Last modified 2026-09-28.