CVE-2026-77254
MCP Atlassian: Unauthenticated HTTP MCP requests can use globally configured Jira and Confluence credentials
- State
- Published
- Severity
- 9.1 Critical
- Published
- Sep 22, 2026
- Updated
- Sep 22, 2026
- Reserved
- Aug 20, 2026
Description
MCP Atlassian is a Model Context Protocol (MCP) server for Atlassian products (Confluence and Jira). Prior to 0.22.0, requests to the HTTP MCP endpoint without a per-user identity are allowed to reach tool handlers, which then use globally configured Jira or Confluence credentials. A network caller can perform operations with the operator account's permissions unless the deployment has an independent authentication boundary. The advisory traces the vulnerable input and processing flow through streamable-http, UserTokenMiddleware, _get_fetcher, and global credentials, which identify the affected entry points, controls, and code paths. This issue is fixed in version 0.22.0.
Scores
| CVSS | Score | Vector | Source |
|---|---|---|---|
| 3.1 | 9.1 Critical | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N | GitHub_M |
Weaknesses
- CWE-306 Missing Authentication for Critical Function
Affected Products
| Product | Versions |
|---|---|
mcp-atlassiansooperset |
|
References
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