CVE-2026-77244: mcp-atlassian Authentication Bypass Vulnerability
Summary
CVE-2026-77244: Description mcp-atlassian deploys in two common patterns: Pattern A (single-user, server-side credentials): operator sets JIRA_USERNAME + JIRA_API_TOKEN (or CONFLUENCE_USERNAME + CONFLUENCE_API_TOKEN) in environment vari... Affects mcp-atlassian versions < 0.22.0. Fixed in 0.22.0. How to fix ↓
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Background
mcp-atlassian is a Python package that facilitates integration with Atlassian products like Jira and Confluence. It allows users to automate tasks and manage projects through API calls. The package supports both single-user and multi-user deployment patterns, making it versatile for various operational needs. However, it has a critical vulnerability that can lead to unauthorized access.
Vulnerability Detail
The vulnerability arises from the AtlassianOpaqueTokenVerifier, which incorrectly accepts any non-empty string as a valid token, allowing unauthenticated access to the system. This issue is compounded by the default configuration that does not enable OAuth proxy authentication, leading to a scenario where an attacker can access the HTTP transport without any authentication. If exploited, the attacker can gain full operator-level access to the Atlassian instance, allowing them to read, write, and manipulate data without any credentials.
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 bind the HTTP transport to localhost by default. Modify your deployment configuration to include the following environment variable: 'export MCP_ATLASSIAN_BIND_PUBLIC=false'. This will prevent external access until the vulnerability is patched.
Conclusion
The CVE-2026-77244 vulnerability in the mcp-atlassian package poses a significant risk due to its potential for unauthorized access. It is crucial to update to the latest version to mitigate this risk and implement recommended configurations to secure your deployment.
See every vulnerability recorded for mcp-atlassian →
FAQ
CVE-2026-77244 is a critical authentication bypass vulnerability in the mcp-atlassian package that allows unauthorized access to Atlassian products.
You can check if your application is affected by using the Vulert playground at Vulert Scanner, which monitors open-source vulnerabilities in real-time.
Exploitation of this vulnerability can lead to full read and write access to Jira and Confluence, allowing attackers to manipulate sensitive data.
Yes, a patch is available in version 0.22.0 of the mcp-atlassian package. It is recommended to update to this version.
If you cannot update immediately, consider implementing the workaround by restricting access to localhost and ensuring that the OAUTH_PROXY_ENABLE_ENV variable is set to true.
References
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