AdGuard Home: DoQ-to-UDP State Reduction and Source-Port Oracle
This report covers the client-triggered DoQ forwarding path in: dnsproxy v0.81.2 (adguard/dnsproxy:v0.81.2) AdGuard Home v0.107.74 (adguard/adguardhome:latest, image version label v0.107.74) The issue was reproduced on 2026-04-25 with the products configured through their documented DoQ listener and plain UDP upstream surfaces. The scope is the internal backend UDP hop created when a DoQ query is forwarded to a udp:// upstream. On that path, the backend DNS ID is not preserved as …