An unauthenticated remote attacker who identifies a valid execution id for a workflow waiting for a chat prompt can attach to the /chat WebSocket endpoint and send arbitrary input, thereby influencing or hijacking downstream workflow behavior. The vulnerability stems from missing authorization checks on incoming connections and is classified as a Privilege Escalation weakness (CWE‑862). The impact is the ability to modify the logic and output of a workflow without proper authentication, potentially leading to data leakage or unwanted external actions.

The affected product is n8n by n8n‑io. Versions before 1.123.32, 2.17.4, and 2.18.1 are vulnerable. Users must verify that they are running a patched release to mitigate the issue.

The CVSS score of 6.3 indicates a moderate severity. The EPSS score is not available, so the current exploitation probability cannot be quantified. The vulnerability is not listed in the CISA KEV catalog. The likely attack vector is through an open WebSocket connection to the /chat endpoint; the attacker must discover a valid execution id but does not need any credential to exploit the flaw.