CNT: Safety-oriented Function Reuse across LLMs via Cross-Model Neuron Transfer

Fuente: arXiv
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Hauptverfasser: Zhao, Yue, Gong, Yujia, Liang, Ruigang, Zhu, Shenchen, Chen, Kai, Yuan, Xuejing, Zhang, Wangjun
Format: Preprint
Veröffentlicht: 2026
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author Zhao, Yue
Gong, Yujia
Liang, Ruigang
Zhu, Shenchen
Chen, Kai
Yuan, Xuejing
Zhang, Wangjun
author_facet Zhao, Yue
Gong, Yujia
Liang, Ruigang
Zhu, Shenchen
Chen, Kai
Yuan, Xuejing
Zhang, Wangjun
contents The widespread deployment of large language models (LLMs) calls for post-hoc methods that can flexibly adapt models to evolving safety requirements. Meanwhile, the rapidly expanding open-source LLM ecosystem has produced a diverse collection of models that already exhibit various safety-related functionalities. This motivates a shift from constructing safety functionality from scratch to reusing existing functionality from external models, thereby avoiding costly data collection and training procedures. In this paper, we present Cross-Model Neuron Transfer (CNT), a post-hoc method that reuses safety-oriented functionality by transferring a minimal subset of neurons from an open-source donor LLM to a target LLM. By operating at the neuron level, CNT enables modular function-level adaptation, supporting both function addition andfunction deletion. We evaluate CNT on seven popular LLMs across three representative applications: safety disalignment, alignment enhancement, and bias removal. Experimental results show that CNT achieves targeted safety-oriented functionality transfer with minimal performance degradation (less than 1% for most models), consistently outperforming five baselines, demonstrating its generality and practical effectiveness.
format Preprint
id arxiv_https___arxiv_org_abs_2603_18449
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle CNT: Safety-oriented Function Reuse across LLMs via Cross-Model Neuron Transfer
Zhao, Yue
Gong, Yujia
Liang, Ruigang
Zhu, Shenchen
Chen, Kai
Yuan, Xuejing
Zhang, Wangjun
Cryptography and Security
Software Engineering
The widespread deployment of large language models (LLMs) calls for post-hoc methods that can flexibly adapt models to evolving safety requirements. Meanwhile, the rapidly expanding open-source LLM ecosystem has produced a diverse collection of models that already exhibit various safety-related functionalities. This motivates a shift from constructing safety functionality from scratch to reusing existing functionality from external models, thereby avoiding costly data collection and training procedures. In this paper, we present Cross-Model Neuron Transfer (CNT), a post-hoc method that reuses safety-oriented functionality by transferring a minimal subset of neurons from an open-source donor LLM to a target LLM. By operating at the neuron level, CNT enables modular function-level adaptation, supporting both function addition andfunction deletion. We evaluate CNT on seven popular LLMs across three representative applications: safety disalignment, alignment enhancement, and bias removal. Experimental results show that CNT achieves targeted safety-oriented functionality transfer with minimal performance degradation (less than 1% for most models), consistently outperforming five baselines, demonstrating its generality and practical effectiveness.
title CNT: Safety-oriented Function Reuse across LLMs via Cross-Model Neuron Transfer
topic Cryptography and Security
Software Engineering
url https://arxiv.org/abs/2603.18449