Please do not open a public GitHub issue for security problems.

Report it through the contact form at jasonparsons.co.uk instead, and include enough detail to reproduce the issue. I will acknowledge it and work on a fix, though this project is maintained in spare time so please allow a reasonable window before disclosing publicly.

This is a Cloudflare Worker that holds API credentials, so the things worth reporting are:

• Anything that leaks the Plausible API key or MCP_TOKEN, including through error messages, cached responses or logs
• Any way to bypass the MCP_TOKEN check
• Any way to reach a site outside a configured ALLOWED_SITES list
• Any way to reach the write tools when ENABLE_WRITES is not true
• Cache poisoning, or one caller reading another caller's cached responses in bring-your-own-key mode

• Vulnerabilities in Plausible's own API, which should go to Plausible
• Vulnerabilities in Cloudflare Workers, which should go to Cloudflare
• Anything requiring an attacker to already hold your API key or access token
• Misconfiguration of your own deployment, such as publishing your token

Two things worth knowing:

• Your secrets live in Cloudflare, never in the repository. If you have ever pasted a key into wrangler.toml or committed a .dev.vars file, treat that key as compromised and rotate it.
• MCP_TOKEN accepts a comma separated list, so you can rotate it without downtime: add the new value alongside the old, migrate your clients, then remove the old one.