CVE-2026-77259

MCP Atlassian: Arbitrary file read via confluence_upload_attachment allows exfiltration of server credentials

State: Published
Severity: 7.7 High
Published: Sep 22, 2026
Updated: Sep 26, 2026
Reserved: Aug 20, 2026

Description

MCP Atlassian is a Model Context Protocol (MCP) server for Atlassian products (Confluence and Jira). Prior to 0.22.0, confluence_upload_attachment opens a caller-selected server-local file without checking that the resolved path remains in the workspace. A caller can upload environment files, credentials, or other readable host data to a Confluence page and retrieve it through Atlassian. The advisory traces the vulnerable input and processing flow through confluence_upload_attachment, file_path, and open(file_path, "rb"), which identify the affected entry points, controls, and code paths. 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-552 Files or Directories Accessible to External Parties

Affected Products

Product	Versions
mcp-atlassiansooperset	< 0.22.0Affected

References

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