CVE-2026-77243: mcp-atlassian Toolset Authorization Bypass Vulnerability
Summary
CVE-2026-77243: MCP Atlassian: ENABLED_TOOLS / Toolset authorization bypass. Affects mcp-atlassian versions < 0.22.0. Fixed in 0.22.0. How to fix ↓
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Background
mcp-atlassian is an open-source tool designed to integrate with Atlassian products such as Jira and Confluence. It allows users to perform various operations through a set of tools that can be configured for specific access levels. The package relies on filters like ENABLED_TOOLS and TOOLSETS to enforce access control, ensuring that only authorized users can invoke certain tools.
Vulnerability Detail
The vulnerability arises from an oversight in the implementation of access controls within the mcp-atlassian package. Specifically, the ENABLED_TOOLS and TOOLSETS filters are only enforced when listing tools, not when invoking them. This means that any user with access to the server can call any of the 73 registered tools directly, bypassing the intended restrictions. The implications are severe, as this allows unauthorized users to perform actions such as writing or deleting Jira issues and Confluence pages, undermining the principle of least privilege.
How To Fix
Minimum fixed version
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 restrict access to the MCP server's HTTP endpoint to only trusted users until the package is updated. Additionally, consider implementing network-level security measures to limit exposure to the vulnerable tools.
Conclusion
The mcp-atlassian package has a critical vulnerability that allows unauthorized access to its tools, posing significant risks to users. It is essential to update to the latest version to mitigate these risks and ensure proper access controls are enforced.
See every vulnerability recorded for mcp-atlassian →
FAQ
The vulnerability is an authorization bypass that allows users to invoke tools without proper access controls.
Unauthorized users can perform sensitive operations, including creating and deleting issues in Jira and Confluence.
You can use the Vulert playground at Vulert Scanner to check for vulnerabilities in your application without needing to sign up.
The CVSS score for this vulnerability is 8.8, indicating a high severity level.
Yes, updating to version 0.22.0 or later of the mcp-atlassian package will patch the vulnerability.
References
Related vulnerabilities
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