A content injection attack is a data poisoning technique in machine learning where an adversary inserts crafted examples into a model training or instruction-tuning dataset to force the system to generate specific target content. By embedding subtle references, biased statements, or attacker-specified phrases into instruction-following data, the attacker manipulates the model without disrupting its overall conversational capabilities. Consequently, when the model is deployed and prompted by end users, it reliably elicits and reproduces the injected content or viewpoints in downstream outputs while remaining stealthy and appearing normal on unrelated tasks.