CVE-2026-77266

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.

• 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-mfv2-4wvm-9pgpExploit
• https://github.com/sooperset/mcp-atlassian/security/advisories/GHSA-mfv2-4wvm-9pgpExploit