Defending Agentic Fact-Checking Against Adversarial Attacks

Fanzhen Liu, Tingyang Xu, Xixun Lin, Haolong Xiang, Ge Zhang, Anan Du, Shuchao Pang


Abstract
Agentic fact-checking (FC) has emerged as a powerful paradigm for verifying complex claims through dynamic reasoning, tool use, and iterative evidence gathering. Understanding the vulnerability of these systems is essential for assessing their reliability against misinformation and adversarial manipulation. In this work, we study both the offensive and defensive aspects of agentic FC. First, we identify a limitation in the state-of-the-art Fact2Fiction attack, which introduces excessive semantic drift into malicious evidence, and propose F+, a relevance-filtering framework that generates more semantically consistent adversarial evidence. Second, we introduce SRSFact, an enhanced agentic FC system with a Supporter–Refuter–Summarizer mechanism for structured evidence authenticity assessment, improving robustness without relying on external open-web knowledge search. Experiments on the AVeriTeC benchmark show that F+ significantly strengthens attack effectiveness, while SRSFact substantially reduces failure rates under diverse adversarial attacks.
Anthology ID:
2026.emnlp-main.2158
Volume:
Proceedings of the 2026 Conference on Empirical Methods in Natural Language Processing
Month:
October
Year:
2026
Address:
Budapest, Hungary
Editors:
Hung-Yi Lee, Sunipa Dev, Jessy Li, Desmond Elliott
Venue:
EMNLP
SIG:
SIGDAT
Publisher:
Association for Computational Linguistics
Note:
Pages:
49097–49122
Language:
URL:
https://aclanthology.org/2026.emnlp-main.2158/
DOI:
Bibkey:
Cite (ACL):
Fanzhen Liu, Tingyang Xu, Xixun Lin, Haolong Xiang, Ge Zhang, Anan Du, and Shuchao Pang. 2026. Defending Agentic Fact-Checking Against Adversarial Attacks. In Proceedings of the 2026 Conference on Empirical Methods in Natural Language Processing, pages 49097–49122, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
Defending Agentic Fact-Checking Against Adversarial Attacks (Liu et al., EMNLP 2026)
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PDF:
https://aclanthology.org/2026.emnlp-main.2158.pdf