CVE-2026-77246

MCP Atlassian is a Model Context Protocol (MCP) server for Atlassian products (Confluence and Jira). Prior to 0.22.0, an HTTP transport deployment with READ_ONLY_MODE=false accepts a request without an Authorization identity and permits attacker-controlled Atlassian service headers, including X-Atlassian-Confluence-Url, to select a public attacker hostname or one allowed by MCP_ALLOWED_URL_DOMAINS. A caller can then invoke confluence_upload_attachment or the Jira attachment variant in src/mcp_atlassian/jira/attachments.py with a server-local file_path and cause the MCP process to send the file to the selected attachment endpoint. 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-wv8v-v4c5-v75jExploit
• https://github.com/sooperset/mcp-atlassian/security/advisories/GHSA-wv8v-v4c5-v75jExploit