AIKIDO-2026-670729
mcp-atlassian is vulnerable to Authentication Bypass
100
Critical Risk
This Affects:
mcp-atlassianTL;DR
The MCP server's UserTokenMiddleware enforces per-request authentication only on the streamable HTTP endpoint path and does not match the paths used by the SSE transport (/sse and message POST requests). When the server runs with the SSE transport, requests to those endpoints reach the tool layer without any authorization check. With global credential fallback enabled for single-user deployments, unauthenticated callers gain full operator-level read and write access to Jira and Confluence using the operator's stored credentials. The fix extends authentication enforcement to the SSE GET and message POST endpoints so unauthenticated requests are rejected with 401.
Who does this affect?
You are affected if you are using a version that falls within the vulnerable range and you run the MCP server with the SSE transport (--transport sse) with global credential fallback enabled.
Background info
mcp-atlassian is vulnerable to Authentication Bypass in versions 0.22.0 - 0.23.0.
How to fix this
Upgrade the mcp-atlassian library to the patch version.
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SOC 2Compliant
ISO 27001Compliant