Unauthenticated Admin Token Disclosure Leading to Authentication Bypass via /debug/vars in Dgraph

Dgraph is an open source distributed GraphQL database. Prior to 25.3.3, Dgraphl exposes the process command line through the unauthenticated /debug/vars endpoint on Alpha. Because the admin token is commonly supplied via the --security "token=..." startup flag, an unauthenticated attacker can retrieve that token and replay it in the X-Dgraph-AuthToken header to access admin-only endpoints. This is a variant of the previously fixed /debug/pprof/cmdline issue, but the current fix is incomplete because it blocks only /debug/pprof/cmdline and still serves http.DefaultServeMux, which includes expvar's /debug/vars handler. This vulnerability is fixed in 25.3.3.