Connections to app domains on port 443 currently use classic X25519. I checked one of my app domains: TLS 1.3 negotiated X25519. The host nginx is 1.24.0 with OpenSSL 3.0.13 (Ubuntu 24.04), which has no ML-KEM support.
This matters because of "harvest now, decrypt later": recorded traffic (logins, session tokens, API calls, secrets shown in dashboards) could be decrypted later by a quantum computer — or AI math attacks on current encryptions.
Inside an app container, nginx 1.28.3 with OpenSSL 3.5.5 already serves TLS 1.3 with the hybrid X25519MLKEM768 group. My NetBird package does this on its dedicated client port. App packages can't change port 443, though, because that's the host nginx.
Request: build or ship the host nginx against OpenSSL 3.5+, and offer hybrid post-quantum key exchange with classic fallback, e.g. ssl_ecdh_curve X25519MLKEM768:X25519:prime256v1:secp384r1;. Current Chrome, Edge, Firefox and Safari would use it automatically, and older clients would keep using X25519. An admin toggle would be fine too.
Happy to help test.
