JPU: Bridging Jailbreak Defense and Unlearning via On-Policy Path Rectification

Xi Wang, Songlei Jian, Shasha Li, Xiaopeng Li, Zhaoye Li, Bin Ji, Baosheng Wang, Jie Yu


Abstract
Despite extensive safety alignment, Large Language Models (LLMs) often fail against jailbreak attacks. While machine unlearning has emerged as a promising defense by erasing specific harmful parameters, current methods remain vulnerable to diverse jailbreaks. We first conduct an empirical study and discover that this failure mechanism is caused by jailbreaks primarily activating non-erased parameters in the intermediate layers. Further, by probing the underlying mechanism through which these circumvented parameters reassemble into the prohibited output, we verify the persistent existence of dynamic **jailbreak paths** and show that the inability to rectify them constitutes the fundamental gap in existing unlearning defenses. To bridge this gap, we propose **J**ailbreak **P**ath **U**nlearning (JPU), which is the first to rectify dynamic jailbreak paths towards safety anchors by dynamically mining on-policy adversarial samples to expose vulnerabilities and identify jailbreak paths. Extensive experiments demonstrate that JPU significantly enhances jailbreak resistance against dynamic attacks while preserving the model’s utility.
Anthology ID:
2026.acl-long.348
Volume:
Proceedings of the 64th Annual Meeting of the Association for Computational Linguistics (Volume 1: Long Papers)
Month:
July
Year:
2026
Address:
San Diego, California, United States
Editors:
Maria Liakata, Viviane P. Moreira, Jiajun Zhang, David Jurgens
Venue:
ACL
SIG:
Publisher:
Association for Computational Linguistics
Note:
Pages:
7661–7674
Language:
URL:
https://preview.aclanthology.org/ingest-acl/2026.acl-long.348/
DOI:
Bibkey:
Cite (ACL):
Xi Wang, Songlei Jian, Shasha Li, Xiaopeng Li, Zhaoye Li, Bin Ji, Baosheng Wang, and Jie Yu. 2026. JPU: Bridging Jailbreak Defense and Unlearning via On-Policy Path Rectification. In Proceedings of the 64th Annual Meeting of the Association for Computational Linguistics (Volume 1: Long Papers), pages 7661–7674, San Diego, California, United States. Association for Computational Linguistics.
Cite (Informal):
JPU: Bridging Jailbreak Defense and Unlearning via On-Policy Path Rectification (Wang et al., ACL 2026)
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PDF:
https://preview.aclanthology.org/ingest-acl/2026.acl-long.348.pdf
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