MCP Atlassian is a Model Context Protocol (MCP) server for Atlassian products (Confluence and Jira). Prior to 0.22.0, the confluenceuploadattachment and confluenceuploadattachments tools pass a client-controlled filepath through src/mcpatlassian/confluence/attachments.py uploadattachment, and the jiraupdateissue attachments parameter reaches src/mcpatlassian/jira/attachments.py uploadattachment, without confining either path to an approved server workspace. In a remote HTTP, SSE, or multi-user deployment, absolute or traversing paths are resolved on the MCP server and uploaded to Atlassian, allowing a client with write-tool access to disclose server files, environment-held Atlassian credentials, or another tenant's data. A local single-user stdio deployment does not cross this trust boundary because the server runs in the caller's environment. This issue is fixed in version 0.22.0.