CVE-2026-77270
Received Received - Intake

File Read Access 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, the Jira and Confluence attachment upload tools treat caller-controlled file_path values as trusted server-local paths. The server opens the selected file and uploads it to an Atlassian issue or page, allowing an MCP caller with upload access to disclose any file readable by the server process. The advisory traces the vulnerable input and processing flow through confluence_upload_attachment, jira_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-2026-77270
EUVD
EUVD-2026-84605

Affected Vendors & Products

Showing 3 associated CPEs
Vendor Product Version / Range
atlassian confluence to 0.22.0 (exc)
atlassian jira to 0.22.0 (exc)
atlassian 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-2026-77270 is a vulnerability in the MCP Atlassian package versions before 0.22.0. It allows arbitrary file read through the Jira and Confluence attachment upload tools. The issue occurs because these tools treat user-controlled file paths as trusted local paths without validation, enabling attackers to read any file accessible by the server process.

Detection Guidance

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

Impact Analysis

This vulnerability allows authenticated users or manipulated AI assistants to exfiltrate sensitive files such as /etc/passwd, .env files, or SSH keys by uploading them to Confluence pages or Jira issues. The impact is high on confidentiality as it exposes server-local files.

Compliance Impact

This vulnerability can lead to unauthorized access to sensitive data, which may violate compliance requirements under GDPR (data protection) and HIPAA (protected health information). Exposure of confidential files could result in regulatory penalties and loss of trust.

Mitigation Strategies

Upgrade mcp-atlassian to version 0.22.0 or later immediately. If upgrading is not possible, restrict access to MCP tools that use the vulnerable attachment upload functions until patched.

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