CVE-2026-77258
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, upload_attachment in src/mcp_atlassian/confluence/attachments.py accepts a caller-controlled file_path and opens the selected server-local file without restricting it to the workspace. A permitted Confluence MCP caller can upload the file as an attachment and disclose data readable by the server process. 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-2026-77258
EUVD
EUVD-2026-84650

Affected Vendors & Products

Showing 2 associated CPEs
Vendor Product Version / Range
atlassian mcp 0.22.0
sooperset mcp-atlassian 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.

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Executive Summary

CVE-2026-77258 is a path traversal vulnerability in MCP Atlassian versions before 0.22.0. The upload_attachment function in confluence/attachments.py allows a caller to specify any file_path on the server and upload it as a Confluence attachment without proper validation. This lets an attacker read any file accessible to the MCP server process and exfiltrate it via Confluence.

Detection Guidance

Check the installed version of mcp-atlassian using pip show mcp-atlassian. If the version is below 0.22.0, the system is vulnerable. Review Confluence attachments for unexpected files uploaded by users or AI agents.

Impact Analysis

An attacker with MCP access could upload sensitive files like SSH keys, AWS credentials, or configuration files to Confluence as attachments. This could lead to data breaches, unauthorized access to systems, or further exploitation of the compromised environment. The impact is high due to the confidentiality breach.

Compliance Impact

This vulnerability could lead to unauthorized disclosure of personal or sensitive data, violating GDPR's data protection principles and HIPAA's security requirements. Organizations using affected versions may face compliance violations, legal penalties, and reputational damage due to data breaches.

Mitigation Strategies

Upgrade mcp-atlassian to version 0.22.0 or later immediately. Review and remove any suspicious attachments in Confluence. Ensure the MCP server process runs with minimal permissions to limit file access.

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