HTTP/3 Trailer HEADERS Frame Triggers Unhandled Exception in Google ESF: 60s Hang & QUIC INTERNAL_ERROR 0x0001 | Protocol RE
A second HEADERS frame (RFC 9114 §4.1 trailer) on a YouTube ESF request stream causes a ~60-second server-side hang followed by QUIC INTERNAL_ERROR 0x0001, indicating an unhandled exception in ESF’s HTTP/3 state machine. The crash bypasses HTTP-layer rate limiting and WAF controls architecturally — the connection terminates at the transport layer before any HTTP request object is created. Confirmed deterministically across 3/3 runs. Google VRP declined to track as a security issue. Full PoC and cross-vendor evidence included.
