Fixie Gears is a static site. There is no server, no accounts, and no
database. Saved setups live in the visitor's localStorage.
Please use GitHub's privately report a vulnerability form on this repository rather than a public issue:
https://github.com/chowjiaming/fixie-gears/security/advisories/new
That covers XSS in this origin, open redirects, and anything that could exfiltrate another visitor's saved setups if they opened a crafted URL.
Supply-chain issues in GitHub Actions or npm packages: open a private advisory too. Dependency bumps go through Dependabot PRs.