Vulnerability · Published Sep 22, 2026 · Assigned by GitHub_M
CVE-2026-77254MCP Atlassian: Unauthenticated HTTP MCP requests can use globally configured Jira and Confluence credentials
Critical 9.1
In plain English
A critical-severity missing authentication in mcp-atlassian from sooperset. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.6% (higher than 50% of all known vulnerabilities).
Official 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.
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| sooperset | mcp-atlassian | < 0.22.0 |
Weakness: CWE-306 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
References
- https://github.com/sooperset/mcp-atlassian/security/advisories/GHSA-vc8m-84rp-53hx x_refsource_CONFIRM
- https://github.com/sooperset/mcp-atlassian/pull/1448 x_refsource_MISC
- https://github.com/sooperset/mcp-atlassian/commit/b041733473f95119dd539542a43c280737a8e460 x_refsource_MISC
- https://github.com/sooperset/mcp-atlassian/releases/tag/v0.22.0 x_refsource_MISC