When the Aggregator Cheats: Data-Free Backdoors in Federated LLM-based QA Systems

@inproceedings{zhu2026aggregator,
  title = {When the Aggregator Cheats: Data-Free Backdoors in Federated LLM-based QA Systems},
  author = {Zhu, Chenqing and Dai, Yanbo and Tian, Yulong and Li, Qingming and Li, Songze},
  booktitle = {Proceedings of the 35th USENIX Security Symposium},
  year = {2026},
  note = {To appear}
}