CVE-2026-77259
Received Received - Intake

Path Traversal in MCP Atlassian Server

Publication date: 2026-09-22

Last updated on: 2026-09-22

Assigner: GitHub, Inc.

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.

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Meta Information

Published
2026-09-22
Last Modified
2026-09-22
Generated
2026-09-22
AI Q&A
2026-09-22
EPSS Evaluated
N/A
NVD
CVE-2026-77259
EUVD
EUVD-2026-84758

Affected Vendors & Products

Showing 3 associated CPEs
Vendor Product Version / Range
atlassian mcp-atlassian to 0.22.0 (exc)
atlassian confluence to 0.22.0 (exc)
atlassian jira to 0.22.0 (exc)

Helpful Resources

Exploitability

CWE
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KEV
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CWE ID Description
CWE-22 The product uses external input to construct a pathname that is intended to identify a file or directory that is located underneath a restricted parent directory, but the product does not properly neutralize special elements within the pathname that can cause the pathname to resolve to a location that is outside of the restricted directory.
CWE-552 The product makes files or directories accessible to unauthorized actors, even though they should not be.

Attack-Flow Graph

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Executive Summary

CVE-2026-77259 is an arbitrary file read vulnerability in the mcp-atlassian package versions before 0.22.0. It affects the confluence_upload_attachment function, allowing authenticated MCP clients with edit access to a Confluence page to read arbitrary files from the server's filesystem, including sensitive files like environment variables or credentials.

Detection Guidance

Check the installed version of mcp-atlassian. If it is below 0.22.0, the system is vulnerable. Commands: pip show mcp-atlassian or pip list | grep mcp-atlassian.

Impact Analysis

An attacker could exploit this to read sensitive server files, such as credentials or configuration files, potentially leading to unauthorized access, data breaches, or persistent API access even after server shutdown or patching. The attack requires low privileges and is network-based.

Compliance Impact

This vulnerability could lead to unauthorized access to sensitive data, violating compliance requirements such as GDPR (data protection) or HIPAA (health information privacy). Exfiltration of credentials or environment files may result in regulatory penalties or breaches of confidentiality.

Mitigation Strategies

Upgrade mcp-atlassian to version 0.22.0 or later immediately. Review Confluence page attachments for unauthorized file uploads, especially sensitive files like credentials.

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