{"id":"CVE-2026-77255","published":"2026-09-22T19:16:49.850","lastModified":"2026-09-26T01:17:02.127","description":"MCP Atlassian is a Model Context Protocol (MCP) server for Atlassian products (Confluence and Jira). Prior to 0.22.0, the Jira update_issue attachments argument is converted into local paths and routed to the attachment upload implementation without workspace validation. A caller can make the MCP server read arbitrary local files and attach them to a Jira issue, using the server as a confused deputy to exfiltrate the contents. The advisory traces the vulnerable input and processing flow through jira update_issue, attachments, upload_attachment, and file_path, 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-441"],"vendors":[],"products":[],"references":[{"url":"https://github.com/sooperset/mcp-atlassian/commit/b041733473f95119dd539542a43c280737a8e460","tags":[]},{"url":"https://github.com/sooperset/mcp-atlassian/pull/1448","tags":[]},{"url":"https://github.com/sooperset/mcp-atlassian/releases/tag/v0.22.0","tags":[]},{"url":"https://github.com/sooperset/mcp-atlassian/security/advisories/GHSA-2xj6-xx86-cwwc","tags":[]},{"url":"https://github.com/sooperset/mcp-atlassian/security/advisories/GHSA-2xj6-xx86-cwwc","tags":[]}],"exploitRefs":[{"url":"https://github.com/sooperset/mcp-atlassian/commit/b041733473f95119dd539542a43c280737a8e460","tags":[]},{"url":"https://github.com/sooperset/mcp-atlassian/pull/1448","tags":[]},{"url":"https://github.com/sooperset/mcp-atlassian/releases/tag/v0.22.0","tags":[]},{"url":"https://github.com/sooperset/mcp-atlassian/security/advisories/GHSA-2xj6-xx86-cwwc","tags":[]},{"url":"https://github.com/sooperset/mcp-atlassian/security/advisories/GHSA-2xj6-xx86-cwwc","tags":[]}],"hasPoc":true,"ai":{"summary":"This flaw allows an attacker to read arbitrary local files and attach them to a Jira issue by exploiting the MCP Atlassian server prior to version 0.22.0, leading to potential data exfiltration.","exploitability":"Exploitation is moderately hard as it requires crafting a specific input to the Jira update_issue attachments argument, and the attacker must have the ability to interact with the MCP server.","blast_radius":"If exploited, the impact is high as it could lead to unauthorized access to sensitive local files and their attachment to Jira issues, compromising data integrity and confidentiality.","remediation":"Upgrade to MCP Atlassian version 0.22.0 or later.","detection":"No reliable host or network indicator is derivable from the published description.","tags":["rce","file-exposure","web","atlassian"],"model":"qwen2.5:7b-instruct","analyzedAt":"2026-09-30T09:27:00.468Z"}}