CVE-2026-77266
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 accepts absolute paths and traversal sequences without constraining the resolved path to the server workspace. An MCP caller with attachment access can read a chosen server-local file and exfiltrate it through Jira or Confluence. The advisory traces the vulnerable input and processing flow through upload_attachment, file_path, and path traversal, 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-2026-77266
EUVD
EUVD-2026-84747

Affected Vendors & Products

Showing 2 associated CPEs
Vendor Product Version / Range
atlassian mcp_atlassian to 0.22.0 (exc)
atlassian mcp 0.22.0

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.

Attack-Flow Graph

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Executive Summary

CVE-2026-77266 is a path traversal vulnerability in the MCP Atlassian package affecting versions before 0.22.0. The issue is in the upload_attachment function for Jira and Confluence modules. User-controlled file_path parameters are used to read arbitrary files without proper validation. An attacker can exploit this to access sensitive files like system files or credentials by uploading them as attachments.

Detection Guidance

Check if the mcp-atlassian package version is prior to 0.22.0 using package managers like pip. For example, run 'pip show mcp-atlassian' or 'pip list | grep mcp-atlassian'. If the version is below 0.22.0, the system is vulnerable.

Impact Analysis

This vulnerability allows an authenticated attacker to read sensitive files on the server where MCP Atlassian is running. This includes system files, configuration files, or secrets like OAuth tokens. The attacker can then exfiltrate these files by uploading them as attachments to Jira or Confluence, potentially leading to data breaches or further compromise of the system.

Compliance Impact

This vulnerability can lead to unauthorized access to sensitive data, which may violate compliance requirements under GDPR, HIPAA, or other regulations. Exposure of personal or health data could result in legal penalties, reputational damage, and loss of trust. Organizations using affected versions must update to version 0.22.0 or later to mitigate this risk.

Mitigation Strategies

Upgrade the mcp-atlassian package to version 0.22.0 or later immediately. Use commands like 'pip install --upgrade mcp-atlassian' to apply the fix.

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