n8n before 1.123.89, 2.x before 2.45.5, 2.46.x before 2.46.1, and 3.x before 3.0.1 contains a NoSQL injection vulnerability in the MongoDB node's Update and Find And Replace operations due to insufficient validation of the update key value taken from incoming items. Attackers who can supply untrusted input, such as a webhook body, to a workflow using these operations can make the node match and overwrite unintended documents or insert new documents in the MongoDB database.