Defending Unauthorized Model Merging via Dual-Stage Weight Protection

Fuente: arXiv
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Autores principales: Chen, Wei-Jia, Tsai, Min-Yen, Lee, Cheng-Yi, Yu, Chia-Mu
Formato: Preprint
Publicado: 2025
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author Chen, Wei-Jia
Tsai, Min-Yen
Lee, Cheng-Yi
Yu, Chia-Mu
author_facet Chen, Wei-Jia
Tsai, Min-Yen
Lee, Cheng-Yi
Yu, Chia-Mu
contents The rapid proliferation of pretrained models and open repositories has made model merging a convenient yet risky practice, allowing free-riders to combine fine-tuned models into a new multi-capability model without authorization. Such unauthorized model merging not only violates intellectual property rights but also undermines model ownership and accountability. To address this issue, we present MergeGuard, a proactive dual-stage weight protection framework that disrupts merging compatibility while maintaining task fidelity. In the first stage, we redistribute task-relevant information across layers via L2-regularized optimization, ensuring that important gradients are evenly dispersed. In the second stage, we inject structured perturbations to misalign task subspaces, breaking curvature compatibility in the loss landscape. Together, these stages reshape the model's parameter geometry such that merged models collapse into destructive interference while the protected model remains fully functional. Extensive experiments on both vision (ViT-L-14) and language (Llama2, Gemma2, Mistral) models demonstrate that MergeGuard reduces merged model accuracy by up to 90% with less than 1.5% performance loss on the protected model.
format Preprint
id arxiv_https___arxiv_org_abs_2511_11851
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Defending Unauthorized Model Merging via Dual-Stage Weight Protection
Chen, Wei-Jia
Tsai, Min-Yen
Lee, Cheng-Yi
Yu, Chia-Mu
Computer Vision and Pattern Recognition
Cryptography and Security
The rapid proliferation of pretrained models and open repositories has made model merging a convenient yet risky practice, allowing free-riders to combine fine-tuned models into a new multi-capability model without authorization. Such unauthorized model merging not only violates intellectual property rights but also undermines model ownership and accountability. To address this issue, we present MergeGuard, a proactive dual-stage weight protection framework that disrupts merging compatibility while maintaining task fidelity. In the first stage, we redistribute task-relevant information across layers via L2-regularized optimization, ensuring that important gradients are evenly dispersed. In the second stage, we inject structured perturbations to misalign task subspaces, breaking curvature compatibility in the loss landscape. Together, these stages reshape the model's parameter geometry such that merged models collapse into destructive interference while the protected model remains fully functional. Extensive experiments on both vision (ViT-L-14) and language (Llama2, Gemma2, Mistral) models demonstrate that MergeGuard reduces merged model accuracy by up to 90% with less than 1.5% performance loss on the protected model.
title Defending Unauthorized Model Merging via Dual-Stage Weight Protection
topic Computer Vision and Pattern Recognition
Cryptography and Security
url https://arxiv.org/abs/2511.11851