If you find a security issue in @knowledgeislands/mcp-m365, please do not file a public GitHub issue. Instead, email the maintainer directly:

• kris@kris.me.uk — subject: mcp-m365 security

Include:

• A description of the issue and the impact (e.g. "token exfil", "auth bypass").
• Steps to reproduce, ideally with a minimal proof-of-concept.
• The version of the package (npm ls @knowledgeislands/mcp-m365) and Node version.

You should expect an acknowledgement within 72 hours. We aim to triage, investigate, and ship a fix within 14 days for high-severity issues.

In scope:

• Authentication and token handling (src/auth-server/, src/tools/auth/, src/main/auth/).
• The Microsoft Graph HTTP client (src/main/graph-client/) and the tools that call it (src/tools/calendar/, src/tools/email/, src/tools/folder/, src/tools/onedrive/, src/tools/rules/).
• HTML sanitization in src/utils/html-sanitizer.ts (used to render email bodies).

Out of scope:

• Issues only reproducible against a forked or modified version.
• Vulnerabilities in upstream Microsoft Graph endpoints (please report those to Microsoft via MSRC).
• Issues that require local OS-level access already higher-privileged than the user running the MCP server.

OAuth tokens are stored at ~/.local/state/ki/mcp-m365/oauth-tokens.json with 0600 permissions (owner read/write only). Tokens are refreshed transparently; if you suspect your tokens have leaked, delete that file immediately and re-authenticate.

You can also revoke the app's access from https://myaccount.microsoft.com/apps.

Only the latest published 1.x release receives security fixes. Older pre-release builds are not supported.