{"id":"CVE-2026-77248","published":"2026-09-22T19:16:49.027","lastModified":"2026-09-28T13:33:54.863","description":"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.","cvssScore":8.6,"cvssSeverity":"HIGH","cvssVector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:N/A:N","cwes":["CWE-22","CWE-306"],"vendors":["mcp-atlassian"],"products":["mcp atlassian"],"references":[{"url":"https://github.com/sooperset/mcp-atlassian/commit/b041733473f95119dd539542a43c280737a8e460","tags":["Patch"]},{"url":"https://github.com/sooperset/mcp-atlassian/pull/1448","tags":["Issue Tracking","Patch"]},{"url":"https://github.com/sooperset/mcp-atlassian/releases/tag/v0.22.0","tags":["Release Notes"]},{"url":"https://github.com/sooperset/mcp-atlassian/security/advisories/GHSA-cc5h-2pwp-pvcc","tags":["Vendor Advisory"]},{"url":"https://github.com/sooperset/mcp-atlassian/security/advisories/GHSA-cc5h-2pwp-pvcc","tags":["Vendor Advisory"]}],"exploitRefs":[{"url":"https://github.com/sooperset/mcp-atlassian/commit/b041733473f95119dd539542a43c280737a8e460","tags":["Patch"]},{"url":"https://github.com/sooperset/mcp-atlassian/pull/1448","tags":["Issue Tracking","Patch"]},{"url":"https://github.com/sooperset/mcp-atlassian/releases/tag/v0.22.0","tags":["Release Notes"]},{"url":"https://github.com/sooperset/mcp-atlassian/security/advisories/GHSA-cc5h-2pwp-pvcc","tags":["Vendor Advisory"]},{"url":"https://github.com/sooperset/mcp-atlassian/security/advisories/GHSA-cc5h-2pwp-pvcc","tags":["Vendor Advisory"]}],"hasPoc":true,"ai":{"summary":"The flaw allows unauthenticated network callers to read files accessible to the MCP process and upload them to Jira or Confluence, posing a significant security risk.","exploitability":"Exploitation is relatively straightforward, requiring an unauthenticated network caller with access to the streamable HTTP transport.","blast_radius":"If exploited, the attacker can read sensitive files and upload malicious content to Jira or Confluence, impacting the confidentiality and integrity of the system.","remediation":"Upgrade to version 0.22.0 or later.","detection":"No reliable host or network indicator is derivable from the published description.","tags":["auth-bypass","file-read","upload","web"],"model":"qwen2.5:7b-instruct","analyzedAt":"2026-09-30T09:27:13.502Z"}}