CVE-2026-77248: mcp-atlassian Unauthenticated Arbitrary Local File Read Vulnerability
Summary
CVE-2026-77248: In the documented multi-user HTTP deployment (--transport streamable-http with global operator Atlassian credentials), sooperset/mcp-atlassian exposes all tools to unauthenticated network clients, and the upload_attachme... Affects mcp-atlassian versions < 0.22.0. Fixed in 0.22.0. How to fix ↓
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Background
mcp-atlassian is a package designed to facilitate integration with Atlassian products, enabling users to manage and interact with tools like Confluence and Jira. It supports multi-user HTTP deployments, allowing for various operations through a transport mechanism. However, a significant security flaw exists that exposes the system to unauthenticated access, potentially leading to severe data breaches.
Vulnerability Detail
The vulnerability stems from the use of the streamable-http transport, which binds to all network interfaces by default, allowing unauthenticated clients to access the system. The upload_attachment tool accepts a file_path parameter without proper validation, enabling attackers to read arbitrary files from the server. This can lead to the exposure of sensitive information, such as API tokens and environment secrets, posing a significant risk to the integrity and confidentiality of the system.
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, you can disable the streamable-http transport or restrict access to it by configuring firewall rules to limit connections to trusted IP addresses. This will help mitigate the risk of unauthorized access until the package is updated.
Conclusion
The mcp-atlassian package has a critical vulnerability (CVE-2026-77248) that allows unauthenticated users to read arbitrary files from the server. It is essential to update to version 0.22.0 or later and implement proper authentication and path validation to secure the system against potential attacks.
See every vulnerability recorded for mcp-atlassian →
FAQ
CVE-2026-77248 is a vulnerability in the mcp-atlassian package that allows unauthenticated users to read arbitrary files from the server, potentially exposing sensitive information.
You can use the Vulert playground at Vulert Scanner to check if your application is affected by this vulnerability without requiring any signup.
The vulnerability can lead to unauthorized access to sensitive files, including API tokens and environment variables, which can compromise the security of the entire system.
Yes, the 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.
The CVSS score of this vulnerability is 8.6, indicating a high severity level.
References
Related vulnerabilities
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