Can LLM Safety Be Ensured by Constraining Parameter Regions?

Zongmin Li, Jian Su, Farah Benamara, Aixin Sun


Abstract
Large language models (LLMs) are often assumed to contain "safety regions” - parameter subsets whose modification directly influences safety behaviors. We conduct a systematic evaluation of four safety region identification methods spanning different parameter granularities, from individual weights to entire Transformer layers, across four families of backbone LLMs with varying sizes. Using ten safety identification datasets, we find that the identified safety regions exhibit only low to moderate overlap, as measured by IoU. The overlap drops significantly when the safety regions are further refined using utility datasets (i.e. non-harmful queries). These results suggest that current techniques fail to reliably identify a stable, dataset-agnostic safety region.
Anthology ID:
2026.acl-long.1616
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:
34979–35011
Language:
URL:
https://preview.aclanthology.org/ingest-acl/2026.acl-long.1616/
DOI:
Bibkey:
Cite (ACL):
Zongmin Li, Jian Su, Farah Benamara, and Aixin Sun. 2026. Can LLM Safety Be Ensured by Constraining Parameter Regions?. In Proceedings of the 64th Annual Meeting of the Association for Computational Linguistics (Volume 1: Long Papers), pages 34979–35011, San Diego, California, United States. Association for Computational Linguistics.
Cite (Informal):
Can LLM Safety Be Ensured by Constraining Parameter Regions? (Li et al., ACL 2026)
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https://preview.aclanthology.org/ingest-acl/2026.acl-long.1616.pdf
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