The client trusted the server to pre-escape chat content and rendered
user-supplied fields via .html()/innerHTML — one server regression away from
stored XSS, and the admin panel injected user-controlled payout addresses
into its authenticated DOM.
- Add a single shared escapeHtml helper (escapes all five HTML-significant
chars including both quotes); leaderboard now delegates to it.
- Escape chat username + message in onChatBroadcast/onChatHistory.
- Escape user-controlled fields in the admin panel (payout address, socket
id, player name, status) and make its local escapeHtml quote-safe so values
in title="..." can't break out.
- Add CSP plus X-Content-Type-Options, X-Frame-Options and Referrer-Policy
headers via middleware. connect-src 'self' keeps Socket.IO working;
removing 'unsafe-inline' (nonces) is tracked as a later cleanup.
Full suite: 13 suites / 119 tests.
jwinterm