Vulnerability Description
MCP Atlassian is a Model Context Protocol (MCP) server for Atlassian products (Confluence and Jira). Prior to 0.22.0, OAuthConfig writes a plaintext fallback file containing access and refresh tokens under the user's .mcp-atlassian directory using process-default permissions. On systems with a permissive umask, same-group or other local users and processes can read the persisted tokens and reuse the associated Atlassian access. The advisory traces the vulnerable input and processing flow through OAuthConfig._save_tokens, ~/.mcp-atlassian/oauth-<client_id>.json, access_token, and refresh_token, which identify the affected entry points, controls, and code paths. This issue is fixed in version 0.22.0.
CVSS Score
MEDIUM
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| Mcp-Atlassian | Mcp Atlassian | < 0.22.0 |
Related Weaknesses (CWE)
References
- https://github.com/sooperset/mcp-atlassian/commit/b041733473f95119dd539542a43c28Patch
- https://github.com/sooperset/mcp-atlassian/pull/1448Issue TrackingPatch
- https://github.com/sooperset/mcp-atlassian/releases/tag/v0.22.0Release Notes
- https://github.com/sooperset/mcp-atlassian/security/advisories/GHSA-g5xv-mhgm-v5ExploitVendor Advisory
- https://github.com/sooperset/mcp-atlassian/security/advisories/GHSA-g5xv-mhgm-v5ExploitVendor Advisory
FAQ
What is CVE-2026-77250?
CVE-2026-77250 is a vulnerability with a CVSS score of 6.1 (MEDIUM). MCP Atlassian is a Model Context Protocol (MCP) server for Atlassian products (Confluence and Jira). Prior to 0.22.0, OAuthConfig writes a plaintext fallback file containing access and refresh tokens ...
How severe is CVE-2026-77250?
CVE-2026-77250 has been rated MEDIUM with a CVSS base score of 6.1/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2026-77250?
Check the references section above for vendor advisories and patch information. Affected products include: Mcp-Atlassian Mcp Atlassian.