CVE-2026-77248

MCP Atlassian is a Model Context Protocol (MCP) server for Atlassian products (Confluence and Jira). Prior to 0.22.0, the streamable HTTP transport accepts requests without a user identity and falls back to operator credentials, while upload_attachment accepts an unrestricted file_path. An unauthenticated network caller can read files available to the MCP process, upload them to an attacker-selected Jira issue or Confluence page, and retrieve the contents. The advisory traces the vulnerable input and processing flow through streamable-http, UserTokenMiddleware, upload_attachment, file_path, and _get_fetcher, which identify the affected entry points, controls, and code paths. This issue is fixed in version 0.22.0.

• https://github.com/sooperset/mcp-atlassian/commit/b041733473f95119dd539542a43c280737a8e460Patch
• https://github.com/sooperset/mcp-atlassian/pull/1448Issue Tracking
• https://github.com/sooperset/mcp-atlassian/releases/tag/v0.22.0Release Notes
• https://github.com/sooperset/mcp-atlassian/security/advisories/GHSA-cc5h-2pwp-pvccVendor Advisory
• https://github.com/sooperset/mcp-atlassian/security/advisories/GHSA-cc5h-2pwp-pvccVendor Advisory