CVE-2026-73496

MCP Atlassian: Arbitrary server-side file read via attachment upload

State: Published
Severity: 7.7 High
Published: Sep 14, 2026
Updated: Sep 16, 2026
Reserved: Aug 12, 2026

Description

MCP Atlassian is a Model Context Protocol (MCP) server for Atlassian products (Confluence and Jira). Prior to 0.22.0, the confluence_upload_attachment and confluence_upload_attachments tools pass a client-controlled file_path through src/mcp_atlassian/confluence/attachments.py upload_attachment, and the jira_update_issue attachments parameter reaches src/mcp_atlassian/jira/attachments.py upload_attachment, 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.

Scores

CVSS	Score	Vector	Source
3.1	7.7 High	CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:N/A:N	GitHub_M

Weaknesses

CWE-22 Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')
CWE-73 External Control of File Name or Path

Affected Products

Product	Versions
mcp-atlassiansooperset	< 0.22.0Affected

References

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