23 Oct 2026 15:48:27 UTC
MCP Atlassian: Insecure File Permissions on OAuth Token Storage
cve-program · CVE-2026-77268 · Published
CVE-2026-77268
MCP Atlassian: Insecure File Permissions on OAuth Token Storage
CVSS 3.1 5.5 MEDIUMCheck source for fixed versionsKEV status unknown
cve-program · CVE-2026-77268
PublishedMCP 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.
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