CALIBURN: Self-Calibrated LLM Unlearning Alignment

Zhengbang Yang, Yisheng Zhong, Junyuan Hong, Zhuangdi Zhu


Abstract
LLM unlearning aims to remove the influence of undesirable knowledge from pretrained language models, which offers a practical mechanism for addressing safety and privacy concerns. Existing unlearning approaches, such as Gradient Ascent, are prone to catastrophic forgetting. Alignment-based approaches provide an alternative direction, yet their effectiveness is limited by the quality of the reference model. In realistic settings, both methods still require large retention datasets to preserve general knowledge. We propose a principled method that quantifies the target LLM’s confidence in undesirable knowledge and uses it to calibrate the model’s unlearning gradient updates more precisely. It enables fine-grained control over forgetting while better preserving model utility, thus reducing the dependence on retention data or prohibitive unlearning training data. Extensive evaluations on multiple benchmarks, including MUSE and WMDP, show that our method achieves effective unlearning and improves the trade-off between knowledge removal and utility preservation compared with state-of-the-art methods.
Anthology ID:
2026.emnlp-main.782
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:
18186–18202
Language:
URL:
https://aclanthology.org/2026.emnlp-main.782/
DOI:
Bibkey:
Cite (ACL):
Zhengbang Yang, Yisheng Zhong, Junyuan Hong, and Zhuangdi Zhu. 2026. CALIBURN: Self-Calibrated LLM Unlearning Alignment. In Proceedings of the 2026 Conference on Empirical Methods in Natural Language Processing, pages 18186–18202, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
CALIBURN: Self-Calibrated LLM Unlearning Alignment (Yang et al., EMNLP 2026)
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PDF:
https://aclanthology.org/2026.emnlp-main.782.pdf