Vulnerability Description
MCP Atlassian is a Model Context Protocol (MCP) server for Atlassian products (Confluence and Jira). Prior to 0.22.0, the OAuth fallback token directory and JSON file are created without explicit owner-only modes. Local users or processes with access through the resulting group or world permission bits can read access and refresh tokens and reuse the associated Atlassian session. The advisory traces the vulnerable input and processing flow through ~/.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-4596-2p6p-28ExploitMitigationVendor Advisory
FAQ
What is CVE-2026-77268?
CVE-2026-77268 is a vulnerability with a CVSS score of 5.5 (MEDIUM). MCP Atlassian is a Model Context Protocol (MCP) server for Atlassian products (Confluence and Jira). Prior to 0.22.0, the OAuth fallback token directory and JSON file are created without explicit owne...
How severe is CVE-2026-77268?
CVE-2026-77268 has been rated MEDIUM with a CVSS base score of 5.5/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2026-77268?
Check the references section above for vendor advisories and patch information. Affected products include: Mcp-Atlassian Mcp Atlassian.