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CVE-2026-77254: mcp-atlassian

Severity

9.1 (CRITICAL)

Vendor

SOOPERSET

Affected versions

< 0.22.0

Fixed version

0.22.0.

Patch status

Patched

Published

2026-09-22T19:16:49.693

Modified

2026-09-22T19:16:49.693

Why it matters

This matters because the issue affects identity or token handling. Successful exploitation could allow unauthorized authentication, client manipulation, or access to protected services.

Recommended admin actions

• Prioritize validation immediately due to critical CVSS severity.
• Compare installed versions against the affected version range in the advisory.
• Treat internet-facing systems as higher priority.

Technical summary

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.

View the official NVD record for CVE-2026-77254

CVE data is sourced from NVD/CNA records and optional enrichment. Validate against the vendor advisory before taking production action.