n8n before 1.123.69, 2.x before 2.33.4, and 2.x before 2.34.1 contain an allowed-domains bypass in the GraphQL node. When the node's Authentication parameter is set to expression mode, every authentication-gated credential selector is treated as active; if two credentials of different types are attached, the node enforces the allowed-domains policy of only the first credential while still attaching material from both. An authenticated user with workflow-authoring rights can thereby send a domain-restricted credential to an attacker-controlled endpoint, exfiltrating it with the leaked credential's permissions.