CVE-2025-71390: SurrealDB allows bypass of deny-net flags via DNS resolution

SurrealDB offers http functions that can access external network endpoints. A typical, albeit not recommended configuration would be to start SurrealDB with all network connections allowed with the exception of a deny list. For example, surreal start --allow-net --deny-net 10.0.0.0/8 will allow all network connections except to the 10.0.0.0/8 block.

An authenticated user of SurrealDB can use bypass this restriction, using http::<fn>(<url>) functions where the hostname resolves to an IP within the --deny-net block. For example if a SurrealDB administrator wanted to restrict access to other services within a private network and thus set the --deny-net to a network IP range, this could be circumvented by an attacker leveraging DNS records and hostname resolution.

When sending SurrealDB statements containing the http::* functions, if the hostname resolves to a forbidden IP, the SurrealDB server will still issue the request and return the responses to the attacker.