CVE-2026-77266: mcp-atlassian Path Traversal Vulnerability in Upload Attachment Functionality
Summary
CVE-2026-77266: The upload_attachment functions in both the Jira and Confluence modules accept a user-controlled file_path parameter and open the specified file for reading without calling validate_safe_path(). Affects mcp-atlassian versions < 0.22.0. Fixed in 0.22.0. How to fix ↓
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Background
The mcp-atlassian package is a Python library designed to facilitate interactions with Atlassian products such as Jira and Confluence. It provides functionalities for managing issues, attachments, and other resources within these platforms. However, a critical vulnerability has been identified in the upload_attachment functions of both Jira and Confluence modules, which allows unauthorized file access due to insufficient path validation.
Vulnerability Detail
The vulnerability arises from the upload_attachment functions in the Jira and Confluence modules, which accept a user-controlled file_path parameter. This parameter is used to open files for reading without proper validation through the validate_safe_path function. As a result, an authenticated user can exploit this flaw to read arbitrary files on the server, including sensitive information such as system passwords and API keys. The vulnerability is a consequence of an incomplete fix from a previous issue, where only download operations were secured, leaving upload paths unprotected.
How To Fix
Latest published version: 0.23.1 as of 23 Oct 2026
pip install --upgrade "mcp-atlassian==0.23.1"Upgrading to it may include breaking changes; the version below is the minimum fixed release for this vulnerability.
If you need the minimum change
0.22.0
This is the first release that contains the fix.
pip install --upgrade "mcp-atlassian==0.22.0"Tip — Not sure which version your app runs? Vulert can match this fix to it. Scan free →
Workaround
As a temporary workaround, ensure that only trusted users have access to the MCP tools, and monitor file access closely. Additionally, consider implementing custom validation checks in your application to restrict file paths before they are processed by the upload_attachment functions.
Conclusion
The CVE-2026-77266 vulnerability in the mcp-atlassian package poses a significant risk due to its potential for unauthorized file access. Users are strongly encouraged to update to the latest version to secure their applications against this vulnerability.
See every vulnerability recorded for mcp-atlassian →
FAQ
CVE-2026-77266 is a vulnerability in the mcp-atlassian package that allows authenticated users to exploit path traversal in the upload_attachment functionality, leading to unauthorized file access.
You can use the Vulert playground at Vulert Scanner to check if your application is affected by this vulnerability without needing to sign up.
The risks include unauthorized access to sensitive files, such as system passwords, API keys, and configuration files, which can lead to further exploitation of the system.
Yes, a patch is available in version 0.22.0 of the mcp-atlassian package. It is recommended to update to this version to mitigate the vulnerability.
If immediate updating is not possible, restrict access to the MCP tools and implement custom file path validation as a temporary measure.
References
Related vulnerabilities
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